21844340 has 48 divisors (see below), whose sum is σ = 52695552. Its totient is φ = 7451136.

The previous prime is 21844313. The next prime is 21844351. The reversal of 21844340 is 4344812.

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, 46949 + ... + 47411.

It is an arithmetic number, because the mean of its divisors is an integer number (1097824).

Almost surely, 2^21844340 is an apocalyptic number.

21844340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21844340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26347776).

21844340 is an abundant number, since it is smaller than the sum of its proper divisors (30851212).

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

21844340 is a wasteful number, since it uses less digits than its factorization.

21844340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 816 (or 814 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 26.

The square root of 21844340 is about 4673.7928922878. The cubic root of 21844340 is about 279.5415115586.

The spelling of 21844340 in words is "twenty-one million, eight hundred forty-four thousand, three hundred forty".