21336464021 has 2 divisors, whose sum is σ = 21336464022. Its totient is φ = 21336464020.

The previous prime is 21336463979. The next prime is 21336464033. The reversal of 21336464021 is 12046463312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11434024900 + 9902439121 = 106930^2 + 99511^2 .

It is a cyclic number.

It is not a de Polignac number, because 21336464021 - 2⁶ = 21336463957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21336464041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10668232010 + 10668232011.

It is an arithmetic number, because the mean of its divisors is an integer number (10668232011).

Almost surely, 2^21336464021 is an apocalyptic number.

It is an amenable number.

21336464021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21336464021 is an equidigital number, since it uses as much as digits as its factorization.

21336464021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 32.

The spelling of 21336464021 in words is "twenty-one billion, three hundred thirty-six million, four hundred sixty-four thousand, twenty-one".