81801955776 has 56 divisors (see below), whose sum is σ = 218138613760. Its totient is φ = 27052607232.

The previous prime is 81801955727. The next prime is 81801955819. The reversal of 81801955776 is 67755910818.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1652986 + ... + 1701753.

Almost surely, 2^81801955776 is an apocalyptic number.

It is an amenable number.

81801955776 is an abundant number, since it is smaller than the sum of its proper divisors (136336657984).

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

81801955776 is a wasteful number, since it uses less digits than its factorization.

81801955776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3354881 (or 3354871 counting only the distinct ones).

The product of its (nonzero) digits is 4233600, while the sum is 57.

The spelling of 81801955776 in words is "eighty-one billion, eight hundred one million, nine hundred fifty-five thousand, seven hundred seventy-six".