721880 has 16 divisors (see below), whose sum is σ = 1624320. Its totient is φ = 288736.

The previous prime is 721859. The next prime is 721883. The reversal of 721880 is 88127.

It is a super-2 number, since 2×721880² = 1042221468800, which contains 22 as substring.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 721880.

It is not an unprimeable number, because it can be changed into a prime (721883) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8984 + ... + 9063.

It is an arithmetic number, because the mean of its divisors is an integer number (101520).

2⁷²¹⁸⁸⁰ is an apocalyptic number.

It is an amenable number.

721880 is an abundant number, since it is smaller than the sum of its proper divisors (902440).

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

721880 is a wasteful number, since it uses less digits than its factorization.

721880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18058 (or 18054 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 26.

The square root of 721880 is about 849.6352158427. The cubic root of 721880 is about 89.7060367704.

The spelling of 721880 in words is "seven hundred twenty-one thousand, eight hundred eighty".