21306625409989 has 2 divisors, whose sum is σ = 21306625409990. Its totient is φ = 21306625409988.

The previous prime is 21306625409987. The next prime is 21306625410013. The reversal of 21306625409989 is 98990452660312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20706294873889 + 600330536100 = 4550417^2 + 774810^2 .

It is a cyclic number.

It is not a de Polignac number, because 21306625409989 - 2¹ = 21306625409987 is a prime.

Together with 21306625409987, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21306625409989.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21306625409987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10653312704994 + 10653312704995.

It is an arithmetic number, because the mean of its divisors is an integer number (10653312704995).

Almost surely, 2^{21306625409989} is an apocalyptic number.

It is an amenable number.

21306625409989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21306625409989 is an equidigital number, since it uses as much as digits as its factorization.

21306625409989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 50388480, while the sum is 64.

The spelling of 21306625409989 in words is "twenty-one trillion, three hundred six billion, six hundred twenty-five million, four hundred nine thousand, nine hundred eighty-nine".