21452944990637 has 2 divisors, whose sum is σ = 21452944990638. Its totient is φ = 21452944990636.

The previous prime is 21452944990567. The next prime is 21452944990667. The reversal of 21452944990637 is 73609944925412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18928233734281 + 2524711256356 = 4350659^2 + 1588934^2 .

It is a cyclic number.

It is not a de Polignac number, because 21452944990637 - 2¹⁰ = 21452944989613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21452944990667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10726472495318 + 10726472495319.

It is an arithmetic number, because the mean of its divisors is an integer number (10726472495319).

Almost surely, 2^{21452944990637} is an apocalyptic number.

It is an amenable number.

21452944990637 is a deficient number, since it is larger than the sum of its proper divisors (1).

21452944990637 is an equidigital number, since it uses as much as digits as its factorization.

21452944990637 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 117573120, while the sum is 65.

The spelling of 21452944990637 in words is "twenty-one trillion, four hundred fifty-two billion, nine hundred forty-four million, nine hundred ninety thousand, six hundred thirty-seven".