81956927451 has 64 divisors (see below), whose sum is σ = 129689911296. Its totient is φ = 45068486400.

The previous prime is 81956927401. The next prime is 81956927467. The reversal of 81956927451 is 15472965918.

It is a happy number.

It is not a de Polignac number, because 81956927451 - 2¹⁰ = 81956926427 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81956927391 and 81956927400.

It is not an unprimeable number, because it can be changed into a prime (81956927401) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 18452391 + ... + 18456831.

It is an arithmetic number, because the mean of its divisors is an integer number (2026404864).

Almost surely, 2^81956927451 is an apocalyptic number.

81956927451 is a deficient number, since it is larger than the sum of its proper divisors (47732983845).

81956927451 is a wasteful number, since it uses less digits than its factorization.

81956927451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4792.

The product of its digits is 5443200, while the sum is 57.

The spelling of 81956927451 in words is "eighty-one billion, nine hundred fifty-six million, nine hundred twenty-seven thousand, four hundred fifty-one".