31645213 has 2 divisors, whose sum is σ = 31645214. Its totient is φ = 31645212.

The previous prime is 31645199. The next prime is 31645223. The reversal of 31645213 is 31254613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24235929 + 7409284 = 4923^2 + 2722^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31645213 is a prime.

It is equal to p_1953250 and since 31645213 and 1953250 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31645223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15822606 + 15822607.

It is an arithmetic number, because the mean of its divisors is an integer number (15822607).

Almost surely, 2^31645213 is an apocalyptic number.

It is an amenable number.

31645213 is a deficient number, since it is larger than the sum of its proper divisors (1).

31645213 is an equidigital number, since it uses as much as digits as its factorization.

31645213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 25.

The square root of 31645213 is about 5625.4078074394. The cubic root of 31645213 is about 316.3025363308.

Adding to 31645213 its reverse (31254613), we get a palindrome (62899826).

The spelling of 31645213 in words is "thirty-one million, six hundred forty-five thousand, two hundred thirteen".