21493684 has 24 divisors (see below), whose sum is σ = 39428928. Its totient is φ = 10232640.

The previous prime is 21493657. The next prime is 21493691. The reversal of 21493684 is 48639412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27864 + ... + 28624.

It is an arithmetic number, because the mean of its divisors is an integer number (1642872).

Almost surely, 2^21493684 is an apocalyptic number.

It is an amenable number.

21493684 is a deficient number, since it is larger than the sum of its proper divisors (17935244).

21493684 is a wasteful number, since it uses less digits than its factorization.

21493684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1095 (or 1093 counting only the distinct ones).

The product of its digits is 41472, while the sum is 37.

The square root of 21493684 is about 4636.1281259258. The cubic root of 21493684 is about 278.0376568557.

The spelling of 21493684 in words is "twenty-one million, four hundred ninety-three thousand, six hundred eighty-four".