21315852737 has 2 divisors, whose sum is σ = 21315852738. Its totient is φ = 21315852736.

The previous prime is 21315852731. The next prime is 21315852757. The reversal of 21315852737 is 73725851312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12825336001 + 8490516736 = 113249^2 + 92144^2 .

It is a cyclic number.

It is not a de Polignac number, because 21315852737 - 2⁴ = 21315852721 is a prime.

It is not a weakly prime, because it can be changed into another prime (21315852731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10657926368 + 10657926369.

It is an arithmetic number, because the mean of its divisors is an integer number (10657926369).

Almost surely, 2^21315852737 is an apocalyptic number.

It is an amenable number.

21315852737 is a deficient number, since it is larger than the sum of its proper divisors (1).

21315852737 is an equidigital number, since it uses as much as digits as its factorization.

21315852737 is an evil number, because the sum of its binary digits is even.

The product of its digits is 352800, while the sum is 44.

The spelling of 21315852737 in words is "twenty-one billion, three hundred fifteen million, eight hundred fifty-two thousand, seven hundred thirty-seven".