31311232002161 has 2 divisors, whose sum is σ = 31311232002162. Its totient is φ = 31311232002160.

The previous prime is 31311232002131. The next prime is 31311232002373. The reversal of 31311232002161 is 16120023211313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25219931583025 + 6091300419136 = 5021945^2 + 2468056^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31311232002161 is a prime.

It is a super-2 number, since 2×31311232002161² (a number of 28 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31311232002161.

It is not a weakly prime, because it can be changed into another prime (31311232002101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15655616001080 + 15655616001081.

It is an arithmetic number, because the mean of its divisors is an integer number (15655616001081).

Almost surely, 2^{31311232002161} is an apocalyptic number.

It is an amenable number.

31311232002161 is a deficient number, since it is larger than the sum of its proper divisors (1).

31311232002161 is an equidigital number, since it uses as much as digits as its factorization.

31311232002161 is an evil number, because the sum of its binary digits is even.

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

Adding to 31311232002161 its reverse (16120023211313), we get a palindrome (47431255213474).

The spelling of 31311232002161 in words is "thirty-one trillion, three hundred eleven billion, two hundred thirty-two million, two thousand, one hundred sixty-one".