81981617080 has 64 divisors (see below), whose sum is σ = 201278688480. Its totient is φ = 29803929600.

The previous prime is 81981617063. The next prime is 81981617089. The reversal of 81981617080 is 8071618918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81981617089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1886800 + ... + 1929760.

Almost surely, 2^81981617080 is an apocalyptic number.

It is an amenable number.

81981617080 is an abundant number, since it is smaller than the sum of its proper divisors (119297071400).

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

81981617080 is a wasteful number, since it uses less digits than its factorization.

81981617080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47320 (or 47316 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 49.

The spelling of 81981617080 in words is "eighty-one billion, nine hundred eighty-one million, six hundred seventeen thousand, eighty".