77681731 has 4 divisors (see below), whose sum is σ = 78955264. Its totient is φ = 76408200.

The previous prime is 77681719. The next prime is 77681777. The reversal of 77681731 is 13718677.

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 77681731 - 2¹⁷ = 77550659 is a prime.

It is a super-2 number, since 2×77681731² = 12068902662312722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77681711) 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, 636675 + ... + 636796.

It is an arithmetic number, because the mean of its divisors is an integer number (19738816).

Almost surely, 2^77681731 is an apocalyptic number.

77681731 is a deficient number, since it is larger than the sum of its proper divisors (1273533).

77681731 is a wasteful number, since it uses less digits than its factorization.

77681731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1273532.

The product of its digits is 49392, while the sum is 40.

The square root of 77681731 is about 8813.7240142859. The cubic root of 77681731 is about 426.6839414257.

The spelling of 77681731 in words is "seventy-seven million, six hundred eighty-one thousand, seven hundred thirty-one".