81653831 has 4 divisors (see below), whose sum is σ = 93318672. Its totient is φ = 69988992.

The previous prime is 81653827. The next prime is 81653833. The reversal of 81653831 is 13835618.

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 81653831 - 2² = 81653827 is a prime.

It is a super-2 number, since 2×81653831² = 13334696233953122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81653791 and 81653800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81653833) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5832410 + ... + 5832423.

It is an arithmetic number, because the mean of its divisors is an integer number (23329668).

Almost surely, 2^81653831 is an apocalyptic number.

81653831 is a deficient number, since it is larger than the sum of its proper divisors (11664841).

81653831 is a wasteful number, since it uses less digits than its factorization.

81653831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11664840.

The product of its digits is 17280, while the sum is 35.

The square root of 81653831 is about 9036.2509371974. The cubic root of 81653831 is about 433.8359347157.

The spelling of 81653831 in words is "eighty-one million, six hundred fifty-three thousand, eight hundred thirty-one".