81551772131076 has 72 divisors (see below), whose sum is σ = 222076974887040. Its totient is φ = 25084383804864.

The previous prime is 81551772131059. The next prime is 81551772131077. The reversal of 81551772131076 is 67013127715518.

81551772131076 is a `hidden beast` number, since 8 + 1 + 5 + 517 + 7 + 2 + 13 + 107 + 6 = 666.

It is not an unprimeable number, because it can be changed into a prime (81551772131077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 28018636 + ... + 30792003.

Almost surely, 2^{81551772131076} is an apocalyptic number.

It is an amenable number.

81551772131076 is an abundant number, since it is smaller than the sum of its proper divisors (140525202755964).

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

81551772131076 is a wasteful number, since it uses less digits than its factorization.

81551772131076 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58813625 (or 58813620 counting only the distinct ones).

The product of its (nonzero) digits is 2469600, while the sum is 54.

The spelling of 81551772131076 in words is "eighty-one trillion, five hundred fifty-one billion, seven hundred seventy-two million, one hundred thirty-one thousand, seventy-six".