31212102211921 has 2 divisors, whose sum is σ = 31212102211922. Its totient is φ = 31212102211920.

The previous prime is 31212102211847. The next prime is 31212102211931. The reversal of 31212102211921 is 12911220121213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20346739261696 + 10865362950225 = 4510736^2 + 3296265^2 .

It is a cyclic number.

It is not a de Polignac number, because 31212102211921 - 2¹⁷ = 31212102080849 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31212102211921.

It is not a weakly prime, because it can be changed into another prime (31212102211931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15606051105960 + 15606051105961.

It is an arithmetic number, because the mean of its divisors is an integer number (15606051105961).

Almost surely, 2^{31212102211921} is an apocalyptic number.

It is an amenable number.

31212102211921 is a deficient number, since it is larger than the sum of its proper divisors (1).

31212102211921 is an equidigital number, since it uses as much as digits as its factorization.

31212102211921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 28.

The spelling of 31212102211921 in words is "thirty-one trillion, two hundred twelve billion, one hundred two million, two hundred eleven thousand, nine hundred twenty-one".