21572525521 has 2 divisors, whose sum is σ = 21572525522. Its totient is φ = 21572525520.

The previous prime is 21572525509. The next prime is 21572525537. The reversal of 21572525521 is 12552527512.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18468810000 + 3103715521 = 135900^2 + 55711^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21572525521 is a prime.

It is not a weakly prime, because it can be changed into another prime (21572525021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10786262760 + 10786262761.

It is an arithmetic number, because the mean of its divisors is an integer number (10786262761).

Almost surely, 2^21572525521 is an apocalyptic number.

It is an amenable number.

21572525521 is a deficient number, since it is larger than the sum of its proper divisors (1).

21572525521 is an equidigital number, since it uses as much as digits as its factorization.

21572525521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 70000, while the sum is 37.

The spelling of 21572525521 in words is "twenty-one billion, five hundred seventy-two million, five hundred twenty-five thousand, five hundred twenty-one".