21042908 has 12 divisors (see below), whose sum is σ = 37520280. Its totient is φ = 10322832.

The previous prime is 21042883. The next prime is 21042911. The reversal of 21042908 is 80924012.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49418 + ... + 49841.

It is an arithmetic number, because the mean of its divisors is an integer number (3126690).

Almost surely, 2^21042908 is an apocalyptic number.

It is an amenable number.

21042908 is a deficient number, since it is larger than the sum of its proper divisors (16477372).

21042908 is a wasteful number, since it uses less digits than its factorization.

21042908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99316 (or 99314 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 21042908 is about 4587.2549525833. The cubic root of 21042908 is about 276.0801944379.

The spelling of 21042908 in words is "twenty-one million, forty-two thousand, nine hundred eight".