31289513 has 2 divisors, whose sum is σ = 31289514. Its totient is φ = 31289512.

The previous prime is 31289491. The next prime is 31289527. The reversal of 31289513 is 31598213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18983449 + 12306064 = 4357^2 + 3508^2 .

It is an emirp because it is prime and its reverse (31598213) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31289513 - 2⁶ = 31289449 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31289513.

It is not a weakly prime, because it can be changed into another prime (31289543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15644756 + 15644757.

It is an arithmetic number, because the mean of its divisors is an integer number (15644757).

Almost surely, 2^31289513 is an apocalyptic number.

It is an amenable number.

31289513 is a deficient number, since it is larger than the sum of its proper divisors (1).

31289513 is an equidigital number, since it uses as much as digits as its factorization.

31289513 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6480, while the sum is 32.

The square root of 31289513 is about 5593.7029774560. The cubic root of 31289513 is about 315.1129619215.

The spelling of 31289513 in words is "thirty-one million, two hundred eighty-nine thousand, five hundred thirteen".