81542913975 has 24 divisors (see below), whose sum is σ = 149797354320. Its totient is φ = 43489553760.

The previous prime is 81542913973. The next prime is 81542914039. The reversal of 81542913975 is 57931924518.

It is a happy number.

81542913975 is a `hidden beast` number, since 8 + 1 + 542 + 9 + 1 + 3 + 97 + 5 = 666.

It is not a de Polignac number, because 81542913975 - 2¹ = 81542913973 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81542913973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 60401484 + ... + 60402833.

It is an arithmetic number, because the mean of its divisors is an integer number (6241556430).

Almost surely, 2^81542913975 is an apocalyptic number.

81542913975 is a deficient number, since it is larger than the sum of its proper divisors (68254440345).

81542913975 is a wasteful number, since it uses less digits than its factorization.

81542913975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120804336 (or 120804325 counting only the distinct ones).

The product of its digits is 2721600, while the sum is 54.

The spelling of 81542913975 in words is "eighty-one billion, five hundred forty-two million, nine hundred thirteen thousand, nine hundred seventy-five".