81451844136 has 64 divisors (see below), whose sum is σ = 243659371200. Its totient is φ = 25062105024.

The previous prime is 81451844093. The next prime is 81451844143. The reversal of 81451844136 is 63144815418.

81451844136 is a `hidden beast` number, since 81 + 4 + 518 + 44 + 13 + 6 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 81451844091 and 81451844100.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14500726 + ... + 14506341.

It is an arithmetic number, because the mean of its divisors is an integer number (3807177675).

Almost surely, 2^81451844136 is an apocalyptic number.

It is an amenable number.

81451844136 is an abundant number, since it is smaller than the sum of its proper divisors (162207527064).

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

81451844136 is a wasteful number, since it uses less digits than its factorization.

81451844136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29007095 (or 29007085 counting only the distinct ones).

The product of its digits is 368640, while the sum is 45.

The spelling of 81451844136 in words is "eighty-one billion, four hundred fifty-one million, eight hundred forty-four thousand, one hundred thirty-six".