81929631077 has 4 divisors (see below), whose sum is σ = 93633864096. Its totient is φ = 70225398060.

The previous prime is 81929631073. The next prime is 81929631107. The reversal of 81929631077 is 77013692918.

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.

It is a cyclic number.

It is not a de Polignac number, because 81929631077 - 2² = 81929631073 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81929631073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5852116499 + ... + 5852116512.

It is an arithmetic number, because the mean of its divisors is an integer number (23408466024).

Almost surely, 2^81929631077 is an apocalyptic number.

It is an amenable number.

81929631077 is a deficient number, since it is larger than the sum of its proper divisors (11704233019).

81929631077 is a wasteful number, since it uses less digits than its factorization.

81929631077 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11704233018.

The product of its (nonzero) digits is 1143072, while the sum is 53.

The spelling of 81929631077 in words is "eighty-one billion, nine hundred twenty-nine million, six hundred thirty-one thousand, seventy-seven".