81994508730 has 48 divisors (see below), whose sum is σ = 213227164800. Its totient is φ = 21860951904.

The previous prime is 81994508663. The next prime is 81994508767. The reversal of 81994508730 is 3780549918.

81994508730 is a `hidden beast` number, since 8 + 19 + 94 + 508 + 7 + 30 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 391371 + ... + 563169.

It is an arithmetic number, because the mean of its divisors is an integer number (4442232600).

Almost surely, 2^81994508730 is an apocalyptic number.

81994508730 is an abundant number, since it is smaller than the sum of its proper divisors (131232656070).

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

81994508730 is a wasteful number, since it uses less digits than its factorization.

81994508730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177115 (or 177112 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 54.

The spelling of 81994508730 in words is "eighty-one billion, nine hundred ninety-four million, five hundred eight thousand, seven hundred thirty".