81477932184864 has 312 divisors, whose sum is σ = 253279286069040. Its totient is φ = 25729771284864.

The previous prime is 81477932184821. The next prime is 81477932184889. The reversal of 81477932184864 is 46848123977418.

81477932184864 is a `hidden beast` number, since 8 + 1 + 47 + 7 + 93 + 2 + 18 + 486 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 81477932184792 and 81477932184801.

It is an unprimeable number.

It is a polite number, since it can be written in 51 ways as a sum of consecutive naturals, for example, 322990047 + ... + 323242209.

Almost surely, 2^{81477932184864} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81477932184864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126639643034520).

81477932184864 is an abundant number, since it is smaller than the sum of its proper divisors (171801353884176).

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

81477932184864 is an frugal number, since it uses more digits than its factorization.

81477932184864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252228 (or 252187 counting only the distinct ones).

The product of its digits is 520224768, while the sum is 72.

The spelling of 81477932184864 in words is "eighty-one trillion, four hundred seventy-seven billion, nine hundred thirty-two million, one hundred eighty-four thousand, eight hundred sixty-four".