31331220113 has 2 divisors, whose sum is σ = 31331220114. Its totient is φ = 31331220112.

The previous prime is 31331220101. The next prime is 31331220139. The reversal of 31331220113 is 31102213313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21364791889 + 9966428224 = 146167^2 + 99832^2 .

It is a cyclic number.

It is not a de Polignac number, because 31331220113 - 2¹⁶ = 31331154577 is a prime.

It is not a weakly prime, because it can be changed into another prime (31331220143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15665610056 + 15665610057.

It is an arithmetic number, because the mean of its divisors is an integer number (15665610057).

Almost surely, 2^31331220113 is an apocalyptic number.

It is an amenable number.

31331220113 is a deficient number, since it is larger than the sum of its proper divisors (1).

31331220113 is an equidigital number, since it uses as much as digits as its factorization.

31331220113 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 20.

Adding to 31331220113 its reverse (31102213313), we get a palindrome (62433433426).

The spelling of 31331220113 in words is "thirty-one billion, three hundred thirty-one million, two hundred twenty thousand, one hundred thirteen".