81073651664 has 40 divisors (see below), whose sum is σ = 162620008320. Its totient is φ = 39130829568.

The previous prime is 81073651657. The next prime is 81073651667. The reversal of 81073651664 is 46615637018.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81073651667) 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, 683534 + ... + 793325.

It is an arithmetic number, because the mean of its divisors is an integer number (4065500208).

Almost surely, 2^81073651664 is an apocalyptic number.

It is an amenable number.

81073651664 is an abundant number, since it is smaller than the sum of its proper divisors (81546356656).

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

81073651664 is a wasteful number, since it uses less digits than its factorization.

81073651664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1476987 (or 1476981 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 47.

The spelling of 81073651664 in words is "eighty-one billion, seventy-three million, six hundred fifty-one thousand, six hundred sixty-four".