21189830 has 16 divisors (see below), whose sum is σ = 38397024. Its totient is φ = 8419200.

The previous prime is 21189827. The next prime is 21189899. The reversal of 21189830 is 3898112.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 5507 + ... + 8526.

It is an arithmetic number, because the mean of its divisors is an integer number (2399814).

Almost surely, 2^21189830 is an apocalyptic number.

21189830 is a deficient number, since it is larger than the sum of its proper divisors (17207194).

21189830 is a wasteful number, since it uses less digits than its factorization.

21189830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14191.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 21189830 is about 4603.2412493807. The cubic root of 21189830 is about 276.7212372800.

The spelling of 21189830 in words is "twenty-one million, one hundred eighty-nine thousand, eight hundred thirty".