77431681 has 4 divisors (see below), whose sum is σ = 77537200. Its totient is φ = 77326164.

The previous prime is 77431667. The next prime is 77431687. The reversal of 77431681 is 18613477.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18613477 = 3877 ⋅4801.

It is a cyclic number.

It is not a de Polignac number, because 77431681 - 2⁷ = 77431553 is a prime.

It is a super-2 number, since 2×77431681² = 11991330444971522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 77431681.

It is not an unprimeable number, because it can be changed into a prime (77431687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51651 + ... + 53128.

It is an arithmetic number, because the mean of its divisors is an integer number (19384300).

Almost surely, 2^77431681 is an apocalyptic number.

It is an amenable number.

77431681 is a deficient number, since it is larger than the sum of its proper divisors (105519).

77431681 is a wasteful number, since it uses less digits than its factorization.

77431681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105518.

The product of its digits is 28224, while the sum is 37.

The square root of 77431681 is about 8799.5273168506. The cubic root of 77431681 is about 426.2256311694.

The spelling of 77431681 in words is "seventy-seven million, four hundred thirty-one thousand, six hundred eighty-one".