21143999 has 2 divisors, whose sum is σ = 21144000. Its totient is φ = 21143998.

The previous prime is 21143981. The next prime is 21144029. The reversal of 21143999 is 99934112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21143999 - 2²⁰ = 20095423 is a prime.

It is a super-3 number, since 3×21143999³ (a number of 23 digits) contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21113999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10571999 + 10572000.

It is an arithmetic number, because the mean of its divisors is an integer number (10572000).

Almost surely, 2^21143999 is an apocalyptic number.

21143999 is a deficient number, since it is larger than the sum of its proper divisors (1).

21143999 is an equidigital number, since it uses as much as digits as its factorization.

21143999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17496, while the sum is 38.

The square root of 21143999 is about 4598.2604319460. The cubic root of 21143999 is about 276.5215885880.

The spelling of 21143999 in words is "twenty-one million, one hundred forty-three thousand, nine hundred ninety-nine".