21499659 has 24 divisors (see below), whose sum is σ = 33259200. Its totient is φ = 13342320.

The previous prime is 21499649. The next prime is 21499663. The reversal of 21499659 is 95699412.

It is not a de Polignac number, because 21499659 - 2¹⁶ = 21434123 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21499619) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9024 + ... + 11154.

It is an arithmetic number, because the mean of its divisors is an integer number (1385800).

Almost surely, 2^21499659 is an apocalyptic number.

21499659 is a deficient number, since it is larger than the sum of its proper divisors (11759541).

21499659 is a wasteful number, since it uses less digits than its factorization.

21499659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2215 (or 2212 counting only the distinct ones).

The product of its digits is 174960, while the sum is 45.

The square root of 21499659 is about 4636.7724766264. The cubic root of 21499659 is about 278.0634182388.

The spelling of 21499659 in words is "twenty-one million, four hundred ninety-nine thousand, six hundred fifty-nine".