77685731 has 4 divisors (see below), whose sum is σ = 78025200. Its totient is φ = 77346264.

The previous prime is 77685709. The next prime is 77685749. The reversal of 77685731 is 13758677.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 77685731 - 2⁶ = 77685667 is a prime.

It is a super-2 number, since 2×77685731² = 12070145602008722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77685931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 169391 + ... + 169848.

It is an arithmetic number, because the mean of its divisors is an integer number (19506300).

Almost surely, 2^77685731 is an apocalyptic number.

77685731 is a deficient number, since it is larger than the sum of its proper divisors (339469).

77685731 is a wasteful number, since it uses less digits than its factorization.

77685731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 339468.

The product of its digits is 246960, while the sum is 44.

The square root of 77685731 is about 8813.9509302015. The cubic root of 77685731 is about 426.6912649257.

The spelling of 77685731 in words is "seventy-seven million, six hundred eighty-five thousand, seven hundred thirty-one".