31221380369 has 2 divisors, whose sum is σ = 31221380370. Its totient is φ = 31221380368.

The previous prime is 31221380363. The next prime is 31221380387. The reversal of 31221380369 is 96308312213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24831456400 + 6389923969 = 157580^2 + 79937^2 .

It is a cyclic number.

It is not a de Polignac number, because 31221380369 - 2⁴ = 31221380353 is a prime.

It is a super-2 number, since 2×31221380369² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31221380363) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15610690184 + 15610690185.

It is an arithmetic number, because the mean of its divisors is an integer number (15610690185).

Almost surely, 2^31221380369 is an apocalyptic number.

It is an amenable number.

31221380369 is a deficient number, since it is larger than the sum of its proper divisors (1).

31221380369 is an equidigital number, since it uses as much as digits as its factorization.

31221380369 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46656, while the sum is 38.

The spelling of 31221380369 in words is "thirty-one billion, two hundred twenty-one million, three hundred eighty thousand, three hundred sixty-nine".