77220 has 96 divisors (see below), whose sum is σ = 282240. Its totient is φ = 17280.

The previous prime is 77213. The next prime is 77237. The reversal of 77220 is 2277.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 10.

It is a zygodrome in base 8.

It is a junction number, because it is equal to n+sod(n) for n = 77193 and 77202.

It is a congruent number.

It is an unprimeable number.

77220 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5934 + ... + 5946.

It is an arithmetic number, because the mean of its divisors is an integer number (2940).

2⁷⁷²²⁰ 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 77220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141120).

77220 is an abundant number, since it is smaller than the sum of its proper divisors (205020).

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

77220 is a wasteful number, since it uses less digits than its factorization.

77220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42 (or 34 counting only the distinct ones).

The product of its (nonzero) digits is 196, while the sum is 18.

The square root of 77220 is about 277.8848682458. The cubic root of 77220 is about 42.5836874659.

Adding to 77220 its reverse (2277), we get a palindrome (79497).

It can be divided in two parts, 7 and 7220, that added together give a palindrome (7227).

The spelling of 77220 in words is "seventy-seven thousand, two hundred twenty", and thus it is an iban number.