31787113 has 2 divisors, whose sum is σ = 31787114. Its totient is φ = 31787112.

The previous prime is 31787111. The next prime is 31787123. The reversal of 31787113 is 31178713.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 29452329 + 2334784 = 5427^2 + 1528^2 .

It is a cyclic number.

It is not a de Polignac number, because 31787113 - 2¹ = 31787111 is a prime.

Together with 31787111, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (31787111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15893556 + 15893557.

It is an arithmetic number, because the mean of its divisors is an integer number (15893557).

Almost surely, 2^31787113 is an apocalyptic number.

It is an amenable number.

31787113 is a deficient number, since it is larger than the sum of its proper divisors (1).

31787113 is an equidigital number, since it uses as much as digits as its factorization.

31787113 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3528, while the sum is 31.

The square root of 31787113 is about 5638.0061191879. The cubic root of 31787113 is about 316.7746078314.

Subtracting from 31787113 its reverse (31178713), we obtain a square (608400 = 780²).

The spelling of 31787113 in words is "thirty-one million, seven hundred eighty-seven thousand, one hundred thirteen".