21204129959 has 2 divisors, whose sum is σ = 21204129960. Its totient is φ = 21204129958.

The previous prime is 21204129949. The next prime is 21204130069. The reversal of 21204129959 is 95992140212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21204129959 - 2²⁴ = 21187352743 is a prime.

It is a super-2 number, since 2×21204129959² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21204129949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10602064979 + 10602064980.

It is an arithmetic number, because the mean of its divisors is an integer number (10602064980).

Almost surely, 2^21204129959 is an apocalyptic number.

21204129959 is a deficient number, since it is larger than the sum of its proper divisors (1).

21204129959 is an equidigital number, since it uses as much as digits as its factorization.

21204129959 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 116640, while the sum is 44.

The spelling of 21204129959 in words is "twenty-one billion, two hundred four million, one hundred twenty-nine thousand, nine hundred fifty-nine".