21289886 has 16 divisors (see below), whose sum is σ = 33145200. Its totient is φ = 10243968.

The previous prime is 21289883. The next prime is 21289889. The reversal of 21289886 is 68898212.

It is an interprime number because it is at equal distance from previous prime (21289883) and next prime (21289889).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21289883) 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, 34085 + ... + 34703.

It is an arithmetic number, because the mean of its divisors is an integer number (2071575).

Almost surely, 2^21289886 is an apocalyptic number.

21289886 is a deficient number, since it is larger than the sum of its proper divisors (11855314).

21289886 is a wasteful number, since it uses less digits than its factorization.

21289886 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1243.

The product of its digits is 110592, while the sum is 44.

The square root of 21289886 is about 4614.0964445924. The cubic root of 21289886 is about 277.1561024142.

The spelling of 21289886 in words is "twenty-one million, two hundred eighty-nine thousand, eight hundred eighty-six".