81311085880 has 16 divisors (see below), whose sum is σ = 182949943320. Its totient is φ = 32524434336.

The previous prime is 81311085847. The next prime is 81311085883. The reversal of 81311085880 is 8858011318.

It is a happy number.

It is a super-2 number, since 2×81311085880² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81311085883) 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, 1016388534 + ... + 1016388613.

Almost surely, 2^81311085880 is an apocalyptic number.

It is an amenable number.

81311085880 is an abundant number, since it is smaller than the sum of its proper divisors (101638857440).

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

81311085880 is a wasteful number, since it uses less digits than its factorization.

81311085880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2032777158 (or 2032777154 counting only the distinct ones).

The product of its (nonzero) digits is 61440, while the sum is 43.

The spelling of 81311085880 in words is "eighty-one billion, three hundred eleven million, eighty-five thousand, eight hundred eighty".