81565703999 has 8 divisors (see below), whose sum is σ = 88645861920. Its totient is φ = 74600670816.

The previous prime is 81565703951. The next prime is 81565704037. The reversal of 81565703999 is 99930756518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81565703999 - 2⁸ = 81565703743 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 (81565703099) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28779707 + ... + 28782540.

It is an arithmetic number, because the mean of its divisors is an integer number (11080732740).

Almost surely, 2^81565703999 is an apocalyptic number.

81565703999 is a deficient number, since it is larger than the sum of its proper divisors (7080157921).

81565703999 is a wasteful number, since it uses less digits than its factorization.

81565703999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57562369.

The product of its (nonzero) digits is 18370800, while the sum is 62.

The spelling of 81565703999 in words is "eighty-one billion, five hundred sixty-five million, seven hundred three thousand, nine hundred ninety-nine".