21888890 has 16 divisors (see below), whose sum is σ = 39463200. Its totient is φ = 8741520.

The previous prime is 21888871. The next prime is 21888899. The reversal of 21888890 is 9888812.

It is not an unprimeable number, because it can be changed into a prime (21888899) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6761 + ... + 9459.

It is an arithmetic number, because the mean of its divisors is an integer number (2466450).

Almost surely, 2^21888890 is an apocalyptic number.

21888890 is a deficient number, since it is larger than the sum of its proper divisors (17574310).

21888890 is a wasteful number, since it uses less digits than its factorization.

21888890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3517.

The product of its (nonzero) digits is 73728, while the sum is 44.

The square root of 21888890 is about 4678.5564012845. The cubic root of 21888890 is about 279.7314176221.

The spelling of 21888890 in words is "twenty-one million, eight hundred eighty-eight thousand, eight hundred ninety".