21387230 has 16 divisors (see below), whose sum is σ = 38736144. Its totient is φ = 8501760.

The previous prime is 21387227. The next prime is 21387251. The reversal of 21387230 is 3278312.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21387230.

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, 4931 + ... + 8190.

It is an arithmetic number, because the mean of its divisors is an integer number (2421009).

Almost surely, 2^21387230 is an apocalyptic number.

21387230 is a deficient number, since it is larger than the sum of its proper divisors (17348914).

21387230 is a wasteful number, since it uses less digits than its factorization.

21387230 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13291.

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 21387230 is about 4624.6329584087. The cubic root of 21387230 is about 277.5778749596.

The spelling of 21387230 in words is "twenty-one million, three hundred eighty-seven thousand, two hundred thirty".