21499205 has 16 divisors (see below), whose sum is σ = 31753344. Its totient is φ = 13608000.

The previous prime is 21499199. The next prime is 21499217. The reversal of 21499205 is 50299412.

It is not a de Polignac number, because 21499205 - 2⁶ = 21499141 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23171 + ... + 24080.

It is an arithmetic number, because the mean of its divisors is an integer number (1984584).

Almost surely, 2^21499205 is an apocalyptic number.

It is an amenable number.

21499205 is a deficient number, since it is larger than the sum of its proper divisors (10254139).

21499205 is a wasteful number, since it uses less digits than its factorization.

21499205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47276.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 21499205 is about 4636.7235199007. The cubic root of 21499205 is about 278.0614609724.

The spelling of 21499205 in words is "twenty-one million, four hundred ninety-nine thousand, two hundred five".