31231320211397 has 2 divisors, whose sum is σ = 31231320211398. Its totient is φ = 31231320211396.

The previous prime is 31231320211261. The next prime is 31231320211423. The reversal of 31231320211397 is 79311202313213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28369535605636 + 2861784605761 = 5326306^2 + 1691681^2 .

It is a cyclic number.

It is not a de Polignac number, because 31231320211397 - 2¹⁸ = 31231319949253 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31231320211397.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31231320201397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15615660105698 + 15615660105699.

It is an arithmetic number, because the mean of its divisors is an integer number (15615660105699).

Almost surely, 2^{31231320211397} is an apocalyptic number.

It is an amenable number.

31231320211397 is a deficient number, since it is larger than the sum of its proper divisors (1).

31231320211397 is an equidigital number, since it uses as much as digits as its factorization.

31231320211397 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40824, while the sum is 38.

The spelling of 31231320211397 in words is "thirty-one trillion, two hundred thirty-one billion, three hundred twenty million, two hundred eleven thousand, three hundred ninety-seven".