21312403999 has 2 divisors, whose sum is σ = 21312404000. Its totient is φ = 21312403998.

The previous prime is 21312403979. The next prime is 21312404021. The reversal of 21312403999 is 99930421312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21312403999 - 2⁵ = 21312403967 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21312403979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656201999 + 10656202000.

It is an arithmetic number, because the mean of its divisors is an integer number (10656202000).

Almost surely, 2^21312403999 is an apocalyptic number.

21312403999 is a deficient number, since it is larger than the sum of its proper divisors (1).

21312403999 is an equidigital number, since it uses as much as digits as its factorization.

21312403999 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 104976, while the sum is 43.

The spelling of 21312403999 in words is "twenty-one billion, three hundred twelve million, four hundred three thousand, nine hundred ninety-nine".