31621613 has 2 divisors, whose sum is σ = 31621614. Its totient is φ = 31621612.

The previous prime is 31621591. The next prime is 31621621. The reversal of 31621613 is 31612613.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31214569 + 407044 = 5587^2 + 638^2 .

It is a cyclic number.

It is not a de Polignac number, because 31621613 - 2⁸ = 31621357 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31621633) by changing a digit.

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, 15810806 + 15810807.

It is an arithmetic number, because the mean of its divisors is an integer number (15810807).

Almost surely, 2^31621613 is an apocalyptic number.

It is an amenable number.

31621613 is a deficient number, since it is larger than the sum of its proper divisors (1).

31621613 is an equidigital number, since it uses as much as digits as its factorization.

31621613 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 23.

The square root of 31621613 is about 5623.3097905059. The cubic root of 31621613 is about 316.2238872970.

The spelling of 31621613 in words is "thirty-one million, six hundred twenty-one thousand, six hundred thirteen".