21142808 has 16 divisors (see below), whose sum is σ = 39707280. Its totient is φ = 10554208.

The previous prime is 21142789. The next prime is 21142811. The reversal of 21142808 is 80824112.

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, 4166 + ... + 7722.

It is an arithmetic number, because the mean of its divisors is an integer number (2481705).

Almost surely, 2^21142808 is an apocalyptic number.

It is an amenable number.

21142808 is a deficient number, since it is larger than the sum of its proper divisors (18564472).

21142808 is a wasteful number, since it uses less digits than its factorization.

21142808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4306 (or 4302 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 26.

The square root of 21142808 is about 4598.1309246258. The cubic root of 21142808 is about 276.5163965176.

The spelling of 21142808 in words is "twenty-one million, one hundred forty-two thousand, eight hundred eight".