21940320 has 96 divisors (see below), whose sum is σ = 70785792. Its totient is φ = 5709312.

The previous prime is 21940313. The next prime is 21940381. The reversal of 21940320 is 2304912.

It is a tau number, because it is divible by the number of its divisors (96).

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, 20109 + ... + 21171.

It is an arithmetic number, because the mean of its divisors is an integer number (737352).

Almost surely, 2^21940320 is an apocalyptic number.

21940320 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 21940320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35392896).

21940320 is an abundant number, since it is smaller than the sum of its proper divisors (48845472).

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

21940320 is a wasteful number, since it uses less digits than its factorization.

21940320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1124 (or 1116 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 21940320 is about 4684.0495300541. The cubic root of 21940320 is about 279.9503313259.

The spelling of 21940320 in words is "twenty-one million, nine hundred forty thousand, three hundred twenty".