81638154308 has 12 divisors (see below), whose sum is σ = 143776750572. Its totient is φ = 40559082720.

The previous prime is 81638154293. The next prime is 81638154349. The reversal of 81638154308 is 80345183618.

It can be written as a sum of positive squares in 2 ways, for example, as 22934679364 + 58703474944 = 151442^2 + 242288^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64997903 + ... + 64999158.

It is an arithmetic number, because the mean of its divisors is an integer number (11981395881).

Almost surely, 2^81638154308 is an apocalyptic number.

It is an amenable number.

81638154308 is a deficient number, since it is larger than the sum of its proper divisors (62138596264).

81638154308 is a wasteful number, since it uses less digits than its factorization.

81638154308 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129997222 (or 129997220 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 47.

The spelling of 81638154308 in words is "eighty-one billion, six hundred thirty-eight million, one hundred fifty-four thousand, three hundred eight".