81561495832 has 16 divisors (see below), whose sum is σ = 153720179640. Its totient is φ = 40569447936.

The previous prime is 81561495797. The next prime is 81561495877. The reversal of 81561495832 is 23859416518.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 81561495832.

It is a congruent number.

It is an unprimeable number.

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, 26410858 + ... + 26413945.

Almost surely, 2^81561495832 is an apocalyptic number.

It is an amenable number.

81561495832 is a deficient number, since it is larger than the sum of its proper divisors (72158683808).

81561495832 is a wasteful number, since it uses less digits than its factorization.

81561495832 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52825002 (or 52824998 counting only the distinct ones).

The product of its digits is 2073600, while the sum is 52.

The spelling of 81561495832 in words is "eighty-one billion, five hundred sixty-one million, four hundred ninety-five thousand, eight hundred thirty-two".