21642494 has 8 divisors (see below), whose sum is σ = 33875280. Its totient is φ = 10350736.

The previous prime is 21642487. The next prime is 21642503. The reversal of 21642494 is 49424612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21642494.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 235199 + ... + 235290.

It is an arithmetic number, because the mean of its divisors is an integer number (4234410).

Almost surely, 2^21642494 is an apocalyptic number.

21642494 is a deficient number, since it is larger than the sum of its proper divisors (12232786).

21642494 is a wasteful number, since it uses less digits than its factorization.

21642494 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 470514.

The product of its digits is 13824, while the sum is 32.

The square root of 21642494 is about 4652.1493957095. The cubic root of 21642494 is about 278.6778397139.

The spelling of 21642494 in words is "twenty-one million, six hundred forty-two thousand, four hundred ninety-four".