• 720 can be written using four 4's:

See also 113.

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720 has 30 divisors (see below), whose sum is σ = 2418. Its totient is φ = 192.

The previous prime is 719. The next prime is 727. The reversal of 720 is 27.

It is a factorial (720 = 6 ! = 1 ⋅ 2 ⋅ 3 ⋅ 4 ⋅ 5 ⋅ 6 ), and thus also a Jordan-Polya number.

720 is nontrivially palindromic in base 11.

It can be written as a sum of positive squares in only one way, i.e., 576 + 144 = 24^2 + 12^2 .

It is a tau number, because it is divible by the number of its divisors (30).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an Ulam number.

720 is an undulating number in base 11.

It is a nialpdrome in base 3, base 6, base 9, base 10, base 12 and base 15.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (727) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 142 + ... + 146.

720 is a highly composite number, because it has more divisors than any smaller number.

720 is a superabundant number, because it has a larger abundancy index than any smaller number.

2⁷²⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1209).

720 is an abundant number, since it is smaller than the sum of its proper divisors (1698).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

720 is a wasteful number, since it uses less digits than its factorization.

720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19 (or 10 counting only the distinct ones).

The product of its (nonzero) digits is 14, while the sum is 9.

The square root of 720 is about 26.8328157300. The cubic root of 720 is about 8.9628094931.

Adding to 720 its reverse (27), we get a palindrome (747).

It can be divided in two parts, 7 and 20, that added together give a cube (27 = 3³).

The spelling of 720 in words is "seven hundred twenty", and thus it is an aban number, an iban number, and an oban number.