21307952489 has 2 divisors, whose sum is σ = 21307952490. Its totient is φ = 21307952488.

The previous prime is 21307952429. The next prime is 21307952521. The reversal of 21307952489 is 98425970312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16469358889 + 4838593600 = 128333^2 + 69560^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21307952489 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21307952429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10653976244 + 10653976245.

It is an arithmetic number, because the mean of its divisors is an integer number (10653976245).

Almost surely, 2^21307952489 is an apocalyptic number.

It is an amenable number.

21307952489 is a deficient number, since it is larger than the sum of its proper divisors (1).

21307952489 is an equidigital number, since it uses as much as digits as its factorization.

21307952489 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1088640, while the sum is 50.

The spelling of 21307952489 in words is "twenty-one billion, three hundred seven million, nine hundred fifty-two thousand, four hundred eighty-nine".