21243524459 has 2 divisors, whose sum is σ = 21243524460. Its totient is φ = 21243524458.

The previous prime is 21243524453. The next prime is 21243524509. The reversal of 21243524459 is 95442534212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21243524459 - 2¹⁶ = 21243458923 is a prime.

It is not a weakly prime, because it can be changed into another prime (21243524453) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621762229 + 10621762230.

It is an arithmetic number, because the mean of its divisors is an integer number (10621762230).

Almost surely, 2^21243524459 is an apocalyptic number.

21243524459 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243524459 is an equidigital number, since it uses as much as digits as its factorization.

21243524459 is an evil number, because the sum of its binary digits is even.

The product of its digits is 345600, while the sum is 41.

The spelling of 21243524459 in words is "twenty-one billion, two hundred forty-three million, five hundred twenty-four thousand, four hundred fifty-nine".