81184631 has 4 divisors (see below), whose sum is σ = 88565064. Its totient is φ = 73804200.

The previous prime is 81184603. The next prime is 81184657. The reversal of 81184631 is 13648118.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81184631 - 2²² = 76990327 is a prime.

It is a super-2 number, since 2×81184631² = 13181888621212322, which 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 (81184331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3690200 + ... + 3690221.

It is an arithmetic number, because the mean of its divisors is an integer number (22141266).

Almost surely, 2^81184631 is an apocalyptic number.

81184631 is a deficient number, since it is larger than the sum of its proper divisors (7380433).

81184631 is a wasteful number, since it uses less digits than its factorization.

81184631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7380432.

The product of its digits is 4608, while the sum is 32.

The square root of 81184631 is about 9010.2514393329. The cubic root of 81184631 is about 433.0033672825.

The spelling of 81184631 in words is "eighty-one million, one hundred eighty-four thousand, six hundred thirty-one".