81689583642 has 16 divisors (see below), whose sum is σ = 172989706752. Its totient is φ = 25628104640.

The previous prime is 81689583623. The next prime is 81689583653. The reversal of 81689583642 is 24638598618.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 400439034 + ... + 400439237.

It is an arithmetic number, because the mean of its divisors is an integer number (10811856672).

Almost surely, 2^81689583642 is an apocalyptic number.

81689583642 is an abundant number, since it is smaller than the sum of its proper divisors (91300123110).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81689583642 is a wasteful number, since it uses less digits than its factorization.

81689583642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 800878293.

The product of its digits is 19906560, while the sum is 60.

The spelling of 81689583642 in words is "eighty-one billion, six hundred eighty-nine million, five hundred eighty-three thousand, six hundred forty-two".