81368031 has 4 divisors (see below), whose sum is σ = 108490712. Its totient is φ = 54245352.

The previous prime is 81368009. The next prime is 81368033. The reversal of 81368031 is 13086318.

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

It is a de Polignac number, because none of the positive numbers 2^k-81368031 is a prime.

It is a super-2 number, since 2×81368031² = 13241512937633922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81368031.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81368033) 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, 13561336 + ... + 13561341.

It is an arithmetic number, because the mean of its divisors is an integer number (27122678).

Almost surely, 2^81368031 is an apocalyptic number.

81368031 is a deficient number, since it is larger than the sum of its proper divisors (27122681).

81368031 is a wasteful number, since it uses less digits than its factorization.

81368031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27122680.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 81368031 is about 9020.4229945164. The cubic root of 81368031 is about 433.3291805651.

The spelling of 81368031 in words is "eighty-one million, three hundred sixty-eight thousand, thirty-one".