31811812 has 6 divisors (see below), whose sum is σ = 55670678. Its totient is φ = 15905904.

The previous prime is 31811807. The next prime is 31811831. The reversal of 31811812 is 21811813.

31811812 is nontrivially palindromic in base 13.

It can be written as a sum of positive squares in only one way, i.e., 28901376 + 2910436 = 5376^2 + 1706^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3976473 + ... + 3976480.

Almost surely, 2^31811812 is an apocalyptic number.

It is an amenable number.

31811812 is a deficient number, since it is larger than the sum of its proper divisors (23858866).

31811812 is a wasteful number, since it uses less digits than its factorization.

31811812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7952957 (or 7952955 counting only the distinct ones).

The product of its digits is 384, while the sum is 25.

The square root of 31811812 is about 5640.1960958818. The cubic root of 31811812 is about 316.8566325863.

Subtracting from 31811812 its reverse (21811813), we obtain a palindrome (9999999).

It can be divided in two parts, 31811 and 812, that added together give a palindrome (32623).

The spelling of 31811812 in words is "thirty-one million, eight hundred eleven thousand, eight hundred twelve".