21499459 has 2 divisors, whose sum is σ = 21499460. Its totient is φ = 21499458.

The previous prime is 21499453. The next prime is 21499477. The reversal of 21499459 is 95499412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21499459 - 2³ = 21499451 is a prime.

It is not a weakly prime, because it can be changed into another prime (21499451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10749729 + 10749730.

It is an arithmetic number, because the mean of its divisors is an integer number (10749730).

Almost surely, 2^21499459 is an apocalyptic number.

21499459 is a deficient number, since it is larger than the sum of its proper divisors (1).

21499459 is an equidigital number, since it uses as much as digits as its factorization.

21499459 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 116640, while the sum is 43.

The square root of 21499459 is about 4636.7509098506. The cubic root of 21499459 is about 278.0625560103.

The spelling of 21499459 in words is "twenty-one million, four hundred ninety-nine thousand, four hundred fifty-nine".