31136813 has 2 divisors, whose sum is σ = 31136814. Its totient is φ = 31136812.

The previous prime is 31136783. The next prime is 31136827. The reversal of 31136813 is 31863113.

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., 25270729 + 5866084 = 5027^2 + 2422^2 .

It is a cyclic number.

It is not a de Polignac number, because 31136813 - 2⁸ = 31136557 is a prime.

It is a super-2 number, since 2×31136813² = 1939002247593938, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31136863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15568406 + 15568407.

It is an arithmetic number, because the mean of its divisors is an integer number (15568407).

Almost surely, 2^31136813 is an apocalyptic number.

It is an amenable number.

31136813 is a deficient number, since it is larger than the sum of its proper divisors (1).

31136813 is an equidigital number, since it uses as much as digits as its factorization.

31136813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1296, while the sum is 26.

The square root of 31136813 is about 5580.0370070457. The cubic root of 31136813 is about 314.5995179292.

Adding to 31136813 its reverse (31863113), we get a palindrome (62999926).

The spelling of 31136813 in words is "thirty-one million, one hundred thirty-six thousand, eight hundred thirteen".