21860244 has 72 divisors (see below), whose sum is σ = 63598080. Its totient is φ = 6201792.

The previous prime is 21860243. The next prime is 21860263. The reversal of 21860244 is 44206812.

21860244 is a `hidden beast` number, since 2 + 18 + 602 + 44 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21860243) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 56002 + ... + 56390.

Almost surely, 2^21860244 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21860244, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31799040).

21860244 is an abundant number, since it is smaller than the sum of its proper divisors (41737836).

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

21860244 is a wasteful number, since it uses less digits than its factorization.

21860244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 629 (or 624 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 21860244 is about 4675.4939845967. The cubic root of 21860244 is about 279.6093361407.

The spelling of 21860244 in words is "twenty-one million, eight hundred sixty thousand, two hundred forty-four".