77215972 has 24 divisors (see below), whose sum is σ = 144055800. Its totient is φ = 36088320.

The previous prime is 77215961. The next prime is 77215973. The reversal of 77215972 is 27951277.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 20575296 + 56640676 = 4536^2 + 7526^2 .

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (77215973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6322 + ... + 13942.

It is an arithmetic number, because the mean of its divisors is an integer number (6002325).

Almost surely, 2^77215972 is an apocalyptic number.

It is an amenable number.

77215972 is a deficient number, since it is larger than the sum of its proper divisors (66839828).

77215972 is a wasteful number, since it uses less digits than its factorization.

77215972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7791 (or 7789 counting only the distinct ones).

The product of its digits is 61740, while the sum is 40.

The square root of 77215972 is about 8787.2619171162. The cubic root of 77215972 is about 425.8294702701.

It can be divided in two parts, 77215 and 972, that added together give a palindrome (78187).

The spelling of 77215972 in words is "seventy-seven million, two hundred fifteen thousand, nine hundred seventy-two".