81575253892 has 18 divisors (see below), whose sum is σ = 156914383934. Its totient is φ = 37079660640.

The previous prime is 81575253787. The next prime is 81575253931. The reversal of 81575253892 is 29835257518.

It can be written as a sum of positive squares in only one way, i.e., 80955044676 + 620209216 = 284526^2 + 24904^2 .

It is a super-2 number, since 2×81575253892² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 84271473 + ... + 84272440.

Almost surely, 2^81575253892 is an apocalyptic number.

It is an amenable number.

81575253892 is a deficient number, since it is larger than the sum of its proper divisors (75339130042).

81575253892 is a wasteful number, since it uses less digits than its factorization.

81575253892 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168543939 (or 168543926 counting only the distinct ones).

The product of its digits is 6048000, while the sum is 55.

The spelling of 81575253892 in words is "eighty-one billion, five hundred seventy-five million, two hundred fifty-three thousand, eight hundred ninety-two".