21964578539 has 2 divisors, whose sum is σ = 21964578540. Its totient is φ = 21964578538.

The previous prime is 21964578529. The next prime is 21964578557. The reversal of 21964578539 is 93587546912.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21964578539 - 2⁴ = 21964578523 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21964578529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10982289269 + 10982289270.

It is an arithmetic number, because the mean of its divisors is an integer number (10982289270).

Almost surely, 2^21964578539 is an apocalyptic number.

21964578539 is a deficient number, since it is larger than the sum of its proper divisors (1).

21964578539 is an equidigital number, since it uses as much as digits as its factorization.

21964578539 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16329600, while the sum is 59.

The spelling of 21964578539 in words is "twenty-one billion, nine hundred sixty-four million, five hundred seventy-eight thousand, five hundred thirty-nine".