81157292998825 has 6 divisors (see below), whose sum is σ = 100635043318574. Its totient is φ = 64925834399040.

The previous prime is 81157292998763. The next prime is 81157292998853. The reversal of 81157292998825 is 52889929275118.

It can be written as a sum of positive squares in 3 ways, for example, as 14693759563536 + 66463533435289 = 3833244^2 + 8152517^2 .

It is not a de Polignac number, because 81157292998825 - 2¹⁷ = 81157292867753 is a prime.

It is a super-2 number, since 2×81157292998825² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1623145859952 + ... + 1623145860001.

Almost surely, 2^{81157292998825} is an apocalyptic number.

It is an amenable number.

81157292998825 is a deficient number, since it is larger than the sum of its proper divisors (19477750319749).

81157292998825 is a wasteful number, since it uses less digits than its factorization.

81157292998825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3246291719963 (or 3246291719958 counting only the distinct ones).

The product of its digits is 522547200, while the sum is 76.

The spelling of 81157292998825 in words is "eighty-one trillion, one hundred fifty-seven billion, two hundred ninety-two million, nine hundred ninety-eight thousand, eight hundred twenty-five".