81634683291 has 32 divisors (see below), whose sum is σ = 129959424000. Its totient is φ = 44593852800.

The previous prime is 81634683269. The next prime is 81634683343. The reversal of 81634683291 is 19238643618.

It is not a de Polignac number, because 81634683291 - 2⁶ = 81634683227 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81634683211) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 602091 + ... + 725108.

It is an arithmetic number, because the mean of its divisors is an integer number (4061232000).

Almost surely, 2^81634683291 is an apocalyptic number.

81634683291 is a deficient number, since it is larger than the sum of its proper divisors (48324740709).

81634683291 is a wasteful number, since it uses less digits than its factorization.

81634683291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1327339.

The product of its digits is 1492992, while the sum is 51.

The spelling of 81634683291 in words is "eighty-one billion, six hundred thirty-four million, six hundred eighty-three thousand, two hundred ninety-one".