21238170 has 16 divisors (see below), whose sum is σ = 50971680. Its totient is φ = 5663504.

The previous prime is 21238157. The next prime is 21238207. The reversal of 21238170 is 7183212.

It is a self number, because there is not a number n which added to its sum of digits gives 21238170.

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, 353940 + ... + 353999.

It is an arithmetic number, because the mean of its divisors is an integer number (3185730).

Almost surely, 2^21238170 is an apocalyptic number.

21238170 is an abundant number, since it is smaller than the sum of its proper divisors (29733510).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21238170 is a wasteful number, since it uses less digits than its factorization.

21238170 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 707949.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 21238170 is about 4608.4889063553. The cubic root of 21238170 is about 276.9315039577.

The spelling of 21238170 in words is "twenty-one million, two hundred thirty-eight thousand, one hundred seventy".