77697728 has 28 divisors (see below), whose sum is σ = 159501840. Its totient is φ = 37508352.

The previous prime is 77697727. The next prime is 77697733. The reversal of 77697728 is 82779677.

It is a self number, because there is not a number n which added to its sum of digits gives 77697728.

It is not an unprimeable number, because it can be changed into a prime (77697727) 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, 19076 + ... + 22787.

Almost surely, 2^77697728 is an apocalyptic number.

It is an amenable number.

77697728 is an abundant number, since it is smaller than the sum of its proper divisors (81804112).

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

77697728 is a wasteful number, since it uses less digits than its factorization.

77697728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41904 (or 41894 counting only the distinct ones).

The product of its digits is 2074464, while the sum is 53.

The square root of 77697728 is about 8814.6314727276. The cubic root of 77697728 is about 426.7132284255.

The spelling of 77697728 in words is "seventy-seven million, six hundred ninety-seven thousand, seven hundred twenty-eight".