81369031 has 4 divisors (see below), whose sum is σ = 83568232. Its totient is φ = 79169832.

The previous prime is 81369019. The next prime is 81369047. The reversal of 81369031 is 13096318.

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 81369031 - 2⁵ = 81368999 is a prime.

It is a super-2 number, since 2×81369031² = 13241838411757922, 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 = 81368984 and 81369002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81369091) 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, 1099545 + ... + 1099618.

It is an arithmetic number, because the mean of its divisors is an integer number (20892058).

Almost surely, 2^81369031 is an apocalyptic number.

81369031 is a deficient number, since it is larger than the sum of its proper divisors (2199201).

81369031 is a wasteful number, since it uses less digits than its factorization.

81369031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2199200.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 81369031 is about 9020.4784241192. The cubic root of 81369031 is about 433.3309557397.

The spelling of 81369031 in words is "eighty-one million, three hundred sixty-nine thousand, thirty-one".