21812814 has 40 divisors (see below), whose sum is σ = 50573160. Its totient is φ = 7018704.

The previous prime is 21812789. The next prime is 21812821. The reversal of 21812814 is 41821812.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 2377 + ... + 7019.

It is an arithmetic number, because the mean of its divisors is an integer number (1264329).

Almost surely, 2^21812814 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21812814, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25286580).

21812814 is an abundant number, since it is smaller than the sum of its proper divisors (28760346).

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

21812814 is a wasteful number, since it uses less digits than its factorization.

21812814 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4686 (or 4677 counting only the distinct ones).

The product of its digits is 1024, while the sum is 27.

The square root of 21812814 is about 4670.4190390157. The cubic root of 21812814 is about 279.4069676495.

The spelling of 21812814 in words is "twenty-one million, eight hundred twelve thousand, eight hundred fourteen".