21440760 has 128 divisors (see below), whose sum is σ = 72230400. Its totient is φ = 5045760.

The previous prime is 21440719. The next prime is 21440801. The reversal of 21440760 is 6704412.

It is an interprime number because it is at equal distance from previous prime (21440719) and next prime (21440801).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21440760.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 48621 + ... + 49059.

It is an arithmetic number, because the mean of its divisors is an integer number (564300).

Almost surely, 2^21440760 is an apocalyptic number.

21440760 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 21440760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36115200).

21440760 is an abundant number, since it is smaller than the sum of its proper divisors (50789640).

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

21440760 is a wasteful number, since it uses less digits than its factorization.

21440760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 501 (or 497 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 21440760 is about 4630.4168278893. The cubic root of 21440760 is about 277.8092648159.

The spelling of 21440760 in words is "twenty-one million, four hundred forty thousand, seven hundred sixty".