81955963616 has 24 divisors (see below), whose sum is σ = 162055406520. Its totient is φ = 40799035008.

The previous prime is 81955963613. The next prime is 81955963627. The reversal of 81955963616 is 61636955918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81955963613) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5584646 + ... + 5599301.

It is an arithmetic number, because the mean of its divisors is an integer number (6752308605).

Almost surely, 2^81955963616 is an apocalyptic number.

It is an amenable number.

81955963616 is a deficient number, since it is larger than the sum of its proper divisors (80099442904).

81955963616 is a wasteful number, since it uses less digits than its factorization.

81955963616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11184186 (or 11184178 counting only the distinct ones).

The product of its digits is 10497600, while the sum is 59.

The spelling of 81955963616 in words is "eighty-one billion, nine hundred fifty-five million, nine hundred sixty-three thousand, six hundred sixteen".