21185814 has 32 divisors (see below), whose sum is σ = 46609920. Its totient is φ = 6378912.

The previous prime is 21185789. The next prime is 21185821. The reversal of 21185814 is 41858112.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 777 + ... + 6555.

It is an arithmetic number, because the mean of its divisors is an integer number (1456560).

Almost surely, 2^21185814 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21185814, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23304960).

21185814 is an abundant number, since it is smaller than the sum of its proper divisors (25424106).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21185814 is a wasteful number, since it uses less digits than its factorization.

21185814 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5844.

The product of its digits is 2560, while the sum is 30.

The square root of 21185814 is about 4602.8050143364. The cubic root of 21185814 is about 276.7037543223.

The spelling of 21185814 in words is "twenty-one million, one hundred eighty-five thousand, eight hundred fourteen".