21625636321 has 2 divisors, whose sum is σ = 21625636322. Its totient is φ = 21625636320.

The previous prime is 21625636273. The next prime is 21625636337. The reversal of 21625636321 is 12363652612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21122262225 + 503374096 = 145335^2 + 22436^2 .

It is a cyclic number.

It is not a de Polignac number, because 21625636321 - 2¹⁵ = 21625603553 is a prime.

It is not a weakly prime, because it can be changed into another prime (21625636421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10812818160 + 10812818161.

It is an arithmetic number, because the mean of its divisors is an integer number (10812818161).

Almost surely, 2^21625636321 is an apocalyptic number.

It is an amenable number.

21625636321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21625636321 is an equidigital number, since it uses as much as digits as its factorization.

21625636321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77760, while the sum is 37.

The spelling of 21625636321 in words is "twenty-one billion, six hundred twenty-five million, six hundred thirty-six thousand, three hundred twenty-one".