21938570 has 16 divisors (see below), whose sum is σ = 39793248. Its totient is φ = 8707920.

The previous prime is 21938569. The next prime is 21938591. The reversal of 21938570 is 7583912.

It is a self number, because there is not a number n which added to its sum of digits gives 21938570.

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, 7064 + ... + 9683.

It is an arithmetic number, because the mean of its divisors is an integer number (2487078).

Almost surely, 2^21938570 is an apocalyptic number.

21938570 is a deficient number, since it is larger than the sum of its proper divisors (17854678).

21938570 is a wasteful number, since it uses less digits than its factorization.

21938570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16885.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 21938570 is about 4683.8627221557. The cubic root of 21938570 is about 279.9428880114.

The spelling of 21938570 in words is "twenty-one million, nine hundred thirty-eight thousand, five hundred seventy".