26564389021 has 2 divisors, whose sum is σ = 26564389022. Its totient is φ = 26564389020.

The previous prime is 26564388997. The next prime is 26564389037. The reversal of 26564389021 is 12098346562.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26533152100 + 31236921 = 162890^2 + 5589^2 .

It is a cyclic number.

It is not a de Polignac number, because 26564389021 - 2²³ = 26556000413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (26564389081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13282194510 + 13282194511.

It is an arithmetic number, because the mean of its divisors is an integer number (13282194511).

Almost surely, 2^26564389021 is an apocalyptic number.

It is an amenable number.

26564389021 is a deficient number, since it is larger than the sum of its proper divisors (1).

26564389021 is an equidigital number, since it uses as much as digits as its factorization.

26564389021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 622080, while the sum is 46.

The spelling of 26564389021 in words is "twenty-six billion, five hundred sixty-four million, three hundred eighty-nine thousand, twenty-one".