21889215 has 24 divisors (see below), whose sum is σ = 39592800. Its totient is φ = 11166144.

The previous prime is 21889207. The next prime is 21889223. The reversal of 21889215 is 51298812.

It is an interprime number because it is at equal distance from previous prime (21889207) and next prime (21889223).

It is not a de Polignac number, because 21889215 - 2³ = 21889207 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21889215.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9540 + ... + 11609.

It is an arithmetic number, because the mean of its divisors is an integer number (1649700).

Almost surely, 2^21889215 is an apocalyptic number.

21889215 is a deficient number, since it is larger than the sum of its proper divisors (17703585).

21889215 is a wasteful number, since it uses less digits than its factorization.

21889215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21183 (or 21180 counting only the distinct ones).

The product of its digits is 11520, while the sum is 36.

The square root of 21889215 is about 4678.5911340915. The cubic root of 21889215 is about 279.7328020727.

The spelling of 21889215 in words is "twenty-one million, eight hundred eighty-nine thousand, two hundred fifteen".