81921303132570 has 48 divisors (see below), whose sum is σ = 232358605251552. Its totient is φ = 19859709850080.

The previous prime is 81921303132521. The next prime is 81921303132593. The reversal of 81921303132570 is 7523130312918.

81921303132570 is a `hidden beast` number, since 8 + 1 + 9 + 2 + 13 + 0 + 31 + 32 + 570 = 666.

It is a super-2 number, since 2×81921303132570² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 41374394532 + ... + 41374396511.

It is an arithmetic number, because the mean of its divisors is an integer number (4840804276074).

Almost surely, 2^{81921303132570} is an apocalyptic number.

81921303132570 is an abundant number, since it is smaller than the sum of its proper divisors (150437302118982).

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

81921303132570 is a wasteful number, since it uses less digits than its factorization.

81921303132570 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82748791067 (or 82748791064 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 45.

The spelling of 81921303132570 in words is "eighty-one trillion, nine hundred twenty-one billion, three hundred three million, one hundred thirty-two thousand, five hundred seventy".