81634184521 has 8 divisors (see below), whose sum is σ = 86060473344. Its totient is φ = 77319953760.

The previous prime is 81634184503. The next prime is 81634184591. The reversal of 81634184521 is 12548143618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81634184521 - 2⁷ = 81634184393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81634184591) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28013020 + ... + 28015933.

It is an arithmetic number, because the mean of its divisors is an integer number (10757559168).

Almost surely, 2^81634184521 is an apocalyptic number.

It is an amenable number.

81634184521 is a deficient number, since it is larger than the sum of its proper divisors (4426288823).

81634184521 is a wasteful number, since it uses less digits than its factorization.

81634184521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56029031.

The product of its digits is 184320, while the sum is 43.

The spelling of 81634184521 in words is "eighty-one billion, six hundred thirty-four million, one hundred eighty-four thousand, five hundred twenty-one".