21425318908897 has 2 divisors, whose sum is σ = 21425318908898. Its totient is φ = 21425318908896.

The previous prime is 21425318908867. The next prime is 21425318908907. The reversal of 21425318908897 is 79880981352412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18847675814881 + 2577643094016 = 4341391^2 + 1605504^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21425318908897 is a prime.

It is not a weakly prime, because it can be changed into another prime (21425318908817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10712659454448 + 10712659454449.

It is an arithmetic number, because the mean of its divisors is an integer number (10712659454449).

Almost surely, 2^{21425318908897} is an apocalyptic number.

It is an amenable number.

21425318908897 is a deficient number, since it is larger than the sum of its proper divisors (1).

21425318908897 is an equidigital number, since it uses as much as digits as its factorization.

21425318908897 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 69672960, while the sum is 67.

The spelling of 21425318908897 in words is "twenty-one trillion, four hundred twenty-five billion, three hundred eighteen million, nine hundred eight thousand, eight hundred ninety-seven".