81909914000 has 40 divisors (see below), whose sum is σ = 198058176888. Its totient is φ = 32763964800.

The previous prime is 81909913973. The next prime is 81909914011. The reversal of 81909914000 is 41990918.

It can be written as a sum of positive squares in 4 ways, for example, as 1763584 + 81908150416 = 1328^2 + 286196^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×81909914000² (a number of 23 digits) contains 22 as substring.

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, 20475479 + ... + 20479478.

Almost surely, 2^81909914000 is an apocalyptic number.

81909914000 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81909914000 is an abundant number, since it is smaller than the sum of its proper divisors (116148262888).

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

81909914000 is a wasteful number, since it uses less digits than its factorization.

81909914000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40954980 (or 40954964 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 41.

The spelling of 81909914000 in words is "eighty-one billion, nine hundred nine million, nine hundred fourteen thousand".