21526340993 has 2 divisors, whose sum is σ = 21526340994. Its totient is φ = 21526340992.

The previous prime is 21526340923. The next prime is 21526341017. The reversal of 21526340993 is 39904362512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21096691009 + 429649984 = 145247^2 + 20728^2 .

It is a cyclic number.

It is not a de Polignac number, because 21526340993 - 2¹⁶ = 21526275457 is a prime.

It is not a weakly prime, because it can be changed into another prime (21526340923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10763170496 + 10763170497.

It is an arithmetic number, because the mean of its divisors is an integer number (10763170497).

Almost surely, 2^21526340993 is an apocalyptic number.

It is an amenable number.

21526340993 is a deficient number, since it is larger than the sum of its proper divisors (1).

21526340993 is an equidigital number, since it uses as much as digits as its factorization.

21526340993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 349920, while the sum is 44.

The spelling of 21526340993 in words is "twenty-one billion, five hundred twenty-six million, three hundred forty thousand, nine hundred ninety-three".