21211031999 has 2 divisors, whose sum is σ = 21211032000. Its totient is φ = 21211031998.

The previous prime is 21211031983. The next prime is 21211032023. The reversal of 21211031999 is 99913011212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21211031999 - 2⁴ = 21211031983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21211031909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605515999 + 10605516000.

It is an arithmetic number, because the mean of its divisors is an integer number (10605516000).

Almost surely, 2^21211031999 is an apocalyptic number.

21211031999 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211031999 is an equidigital number, since it uses as much as digits as its factorization.

21211031999 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8748, while the sum is 38.

The spelling of 21211031999 in words is "twenty-one billion, two hundred eleven million, thirty-one thousand, nine hundred ninety-nine".