21887288 has 16 divisors (see below), whose sum is σ = 41712360. Its totient is φ = 10764000.

The previous prime is 21887287. The next prime is 21887293. The reversal of 21887288 is 88278812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21887287) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21938 + ... + 22913.

Almost surely, 2^21887288 is an apocalyptic number.

It is an amenable number.

21887288 is a deficient number, since it is larger than the sum of its proper divisors (19825072).

21887288 is a wasteful number, since it uses less digits than its factorization.

21887288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44918 (or 44914 counting only the distinct ones).

The product of its digits is 114688, while the sum is 44.

The square root of 21887288 is about 4678.3851914950. The cubic root of 21887288 is about 279.7245931453.

The spelling of 21887288 in words is "twenty-one million, eight hundred eighty-seven thousand, two hundred eighty-eight".