31244636021 has 2 divisors, whose sum is σ = 31244636022. Its totient is φ = 31244636020.

The previous prime is 31244635909. The next prime is 31244636023. The reversal of 31244636021 is 12063644213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31244451121 + 184900 = 176761^2 + 430^2 .

It is a cyclic number.

It is not a de Polignac number, because 31244636021 - 2¹⁰ = 31244634997 is a prime.

Together with 31244636023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31244636023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15622318010 + 15622318011.

It is an arithmetic number, because the mean of its divisors is an integer number (15622318011).

Almost surely, 2^31244636021 is an apocalyptic number.

It is an amenable number.

31244636021 is a deficient number, since it is larger than the sum of its proper divisors (1).

31244636021 is an equidigital number, since it uses as much as digits as its factorization.

31244636021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 32.

The spelling of 31244636021 in words is "thirty-one billion, two hundred forty-four million, six hundred thirty-six thousand, twenty-one".