21204111999 has 32 divisors (see below), whose sum is σ = 34142699520. Its totient is φ = 11443097952.

The previous prime is 21204111991. The next prime is 21204112001. The reversal of 21204111999 is 99911140212.

It is not a de Polignac number, because 21204111999 - 2³ = 21204111991 is a prime.

It is a super-2 number, since 2×21204111999² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21204111991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 239697 + ... + 316010.

It is an arithmetic number, because the mean of its divisors is an integer number (1066959360).

Almost surely, 2^21204111999 is an apocalyptic number.

21204111999 is a deficient number, since it is larger than the sum of its proper divisors (12938587521).

21204111999 is a wasteful number, since it uses less digits than its factorization.

21204111999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555819.

The product of its (nonzero) digits is 11664, while the sum is 39.

The spelling of 21204111999 in words is "twenty-one billion, two hundred four million, one hundred eleven thousand, nine hundred ninety-nine".