21389804 has 24 divisors (see below), whose sum is σ = 38132640. Its totient is φ = 10497024.

The previous prime is 21389789. The next prime is 21389807. The reversal of 21389804 is 40898312.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21389807) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79382 + ... + 79650.

It is an arithmetic number, because the mean of its divisors is an integer number (1588860).

Almost surely, 2^21389804 is an apocalyptic number.

It is an amenable number.

21389804 is a deficient number, since it is larger than the sum of its proper divisors (16742836).

21389804 is a wasteful number, since it uses less digits than its factorization.

21389804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 569 (or 567 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 21389804 is about 4624.9112423916. The cubic root of 21389804 is about 277.5890102147.

The spelling of 21389804 in words is "twenty-one million, three hundred eighty-nine thousand, eight hundred four".