21463999 has 2 divisors, whose sum is σ = 21464000. Its totient is φ = 21463998.

The previous prime is 21463969. The next prime is 21464017. The reversal of 21463999 is 99936412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21463999 - 2¹⁵ = 21431231 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21463909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10731999 + 10732000.

It is an arithmetic number, because the mean of its divisors is an integer number (10732000).

Almost surely, 2^21463999 is an apocalyptic number.

21463999 is a deficient number, since it is larger than the sum of its proper divisors (1).

21463999 is an equidigital number, since it uses as much as digits as its factorization.

21463999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 104976, while the sum is 43.

The square root of 21463999 is about 4632.9255336126. The cubic root of 21463999 is about 277.9095982994.

The spelling of 21463999 in words is "twenty-one million, four hundred sixty-three thousand, nine hundred ninety-nine".