21284392 has 16 divisors (see below), whose sum is σ = 40024800. Its totient is φ = 10611120.

The previous prime is 21284387. The next prime is 21284401. The reversal of 21284392 is 29348212.

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, 834 + ... + 6577.

It is an arithmetic number, because the mean of its divisors is an integer number (2501550).

Almost surely, 2^21284392 is an apocalyptic number.

It is an amenable number.

21284392 is a deficient number, since it is larger than the sum of its proper divisors (18740408).

21284392 is a wasteful number, since it uses less digits than its factorization.

21284392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7776 (or 7772 counting only the distinct ones).

The product of its digits is 6912, while the sum is 31.

The square root of 21284392 is about 4613.5010566814. The cubic root of 21284392 is about 277.1322596902.

The spelling of 21284392 in words is "twenty-one million, two hundred eighty-four thousand, three hundred ninety-two".