31245646021 has 2 divisors, whose sum is σ = 31245646022. Its totient is φ = 31245646020.

The previous prime is 31245645997. The next prime is 31245646037. The reversal of 31245646021 is 12064654213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30328222500 + 917423521 = 174150^2 + 30289^2 .

It is an emirp because it is prime and its reverse (12064654213) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31245646021 - 2¹⁵ = 31245613253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31245646051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15622823010 + 15622823011.

It is an arithmetic number, because the mean of its divisors is an integer number (15622823011).

Almost surely, 2^31245646021 is an apocalyptic number.

It is an amenable number.

31245646021 is a deficient number, since it is larger than the sum of its proper divisors (1).

31245646021 is an equidigital number, since it uses as much as digits as its factorization.

31245646021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34560, while the sum is 34.

The spelling of 31245646021 in words is "thirty-one billion, two hundred forty-five million, six hundred forty-six thousand, twenty-one".