31031221057 has 2 divisors, whose sum is σ = 31031221058. Its totient is φ = 31031221056.

The previous prime is 31031221033. The next prime is 31031221127. The reversal of 31031221057 is 75012213013.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18199089216 + 12832131841 = 134904^2 + 113279^2 .

It is an emirp because it is prime and its reverse (75012213013) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31031221057 - 2²⁷ = 30897003329 is a prime.

It is not a weakly prime, because it can be changed into another prime (31031221157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15515610528 + 15515610529.

It is an arithmetic number, because the mean of its divisors is an integer number (15515610529).

Almost surely, 2^31031221057 is an apocalyptic number.

It is an amenable number.

31031221057 is a deficient number, since it is larger than the sum of its proper divisors (1).

31031221057 is an equidigital number, since it uses as much as digits as its factorization.

31031221057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1260, while the sum is 25.

The spelling of 31031221057 in words is "thirty-one billion, thirty-one million, two hundred twenty-one thousand, fifty-seven".