21143807999 has 4 divisors (see below), whose sum is σ = 21144555336. Its totient is φ = 21143060664.

The previous prime is 21143807989. The next prime is 21143808011. The reversal of 21143807999 is 99970834112.

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

It is a cyclic number.

It is not a de Polignac number, because 21143807999 - 2¹² = 21143803903 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21143807999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21143807989) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 329489 + ... + 388394.

It is an arithmetic number, because the mean of its divisors is an integer number (5286138834).

Almost surely, 2^21143807999 is an apocalyptic number.

21143807999 is a deficient number, since it is larger than the sum of its proper divisors (747337).

21143807999 is an equidigital number, since it uses as much as digits as its factorization.

21143807999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 747336.

The product of its (nonzero) digits is 979776, while the sum is 53.

The spelling of 21143807999 in words is "twenty-one billion, one hundred forty-three million, eight hundred seven thousand, nine hundred ninety-nine".