81477947744928 has 288 divisors, whose sum is σ = 280410657770880. Its totient is φ = 21907640401920.

The previous prime is 81477947744903. The next prime is 81477947744939. The reversal of 81477947744928 is 82944774977418.

81477947744928 is a `hidden beast` number, since 8 + 1 + 47 + 79 + 47 + 7 + 449 + 28 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 325150308 + ... + 325400796.

It is an arithmetic number, because the mean of its divisors is an integer number (973648117260).

Almost surely, 2^{81477947744928} 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 81477947744928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140205328885440).

81477947744928 is an abundant number, since it is smaller than the sum of its proper divisors (198932710025952).

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

81477947744928 is a wasteful number, since it uses less digits than its factorization.

81477947744928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260020 (or 260009 counting only the distinct ones).

The product of its digits is 6372753408, while the sum is 81.

The spelling of 81477947744928 in words is "eighty-one trillion, four hundred seventy-seven billion, nine hundred forty-seven million, seven hundred forty-four thousand, nine hundred twenty-eight".