21862144 has 72 divisors (see below), whose sum is σ = 47093760. Its totient is φ = 10103808.

The previous prime is 21862123. The next prime is 21862193. The reversal of 21862144 is 44126812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 276697 + ... + 276775.

It is an arithmetic number, because the mean of its divisors is an integer number (654080).

Almost surely, 2^21862144 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 21862144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23546880).

21862144 is an abundant number, since it is smaller than the sum of its proper divisors (25231616).

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

21862144 is an equidigital number, since it uses as much as digits as its factorization.

21862144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 151 counting only the distinct ones).

The product of its digits is 3072, while the sum is 28.

The square root of 21862144 is about 4675.6971672682. The cubic root of 21862144 is about 279.6174367265.

Adding to 21862144 its reverse (44126812), we get a palindrome (65988956).

The spelling of 21862144 in words is "twenty-one million, eight hundred sixty-two thousand, one hundred forty-four".