21909230 has 16 divisors (see below), whose sum is σ = 45070560. Its totient is φ = 7511712.

The previous prime is 21909229. The next prime is 21909247. The reversal of 21909230 is 3290912.

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 21909230.

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, 156425 + ... + 156564.

It is an arithmetic number, because the mean of its divisors is an integer number (2816910).

Almost surely, 2^21909230 is an apocalyptic number.

21909230 is an abundant number, since it is smaller than the sum of its proper divisors (23161330).

21909230 is a wasteful number, since it uses less digits than its factorization.

21909230 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 313003.

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 21909230 is about 4680.7296439765. The cubic root of 21909230 is about 279.8180365350.

The spelling of 21909230 in words is "twenty-one million, nine hundred nine thousand, two hundred thirty".