21642884 has 12 divisors (see below), whose sum is σ = 38035200. Its totient is φ = 10775688.

The previous prime is 21642883. The next prime is 21642893. The reversal of 21642884 is 48824612.

It is not an unprimeable number, because it can be changed into a prime (21642883) by changing a digit.

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, 10364 + ... + 12275.

It is an arithmetic number, because the mean of its divisors is an integer number (3169600).

Almost surely, 2^21642884 is an apocalyptic number.

It is an amenable number.

21642884 is a deficient number, since it is larger than the sum of its proper divisors (16392316).

21642884 is a wasteful number, since it uses less digits than its factorization.

21642884 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22882 (or 22880 counting only the distinct ones).

The product of its digits is 24576, while the sum is 35.

The square root of 21642884 is about 4652.1913116294. The cubic root of 21642884 is about 278.6795136384.

The spelling of 21642884 in words is "twenty-one million, six hundred forty-two thousand, eight hundred eighty-four".