21001324199 has 4 divisors (see below), whose sum is σ = 21001950864. Its totient is φ = 21000697536.

The previous prime is 21001324189. The next prime is 21001324231. The reversal of 21001324199 is 99142310012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21001324199 is a prime.

It is a super-2 number, since 2×21001324199² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001324129) 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 in 3 ways as a sum of consecutive naturals, for example, 260042 + ... + 331095.

It is an arithmetic number, because the mean of its divisors is an integer number (5250487716).

Almost surely, 2^21001324199 is an apocalyptic number.

21001324199 is a deficient number, since it is larger than the sum of its proper divisors (626665).

21001324199 is an equidigital number, since it uses as much as digits as its factorization.

21001324199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 626664.

The product of its (nonzero) digits is 3888, while the sum is 32.

The spelling of 21001324199 in words is "twenty-one billion, one million, three hundred twenty-four thousand, one hundred ninety-nine".