81635138231 has 8 divisors (see below), whose sum is σ = 83231364240. Its totient is φ = 80040984192.

The previous prime is 81635138227. The next prime is 81635138309. The reversal of 81635138231 is 13283153618.

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 81635138231 - 2² = 81635138227 is a prime.

It is a super-2 number, since 2×81635138231² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81635138531) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 438305 + ... + 596138.

It is an arithmetic number, because the mean of its divisors is an integer number (10403920530).

Almost surely, 2^81635138231 is an apocalyptic number.

81635138231 is a deficient number, since it is larger than the sum of its proper divisors (1596226009).

81635138231 is a wasteful number, since it uses less digits than its factorization.

81635138231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1035985.

The product of its digits is 103680, while the sum is 41.

The spelling of 81635138231 in words is "eighty-one billion, six hundred thirty-five million, one hundred thirty-eight thousand, two hundred thirty-one".