21978752 has 64 divisors (see below), whose sum is σ = 47001600. Its totient is φ = 10214400.

The previous prime is 21978743. The next prime is 21978779. The reversal of 21978752 is 25787912.

It is a tau number, because it is divible by the number of its divisors (64).

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, 114977 + ... + 115167.

It is an arithmetic number, because the mean of its divisors is an integer number (734400).

Almost surely, 2^21978752 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 21978752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23500800).

21978752 is an abundant number, since it is smaller than the sum of its proper divisors (25022848).

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

21978752 is a wasteful number, since it uses less digits than its factorization.

21978752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265 (or 253 counting only the distinct ones).

The product of its digits is 70560, while the sum is 41.

The square root of 21978752 is about 4688.1501682433. The cubic root of 21978752 is about 280.1136953238.

The spelling of 21978752 in words is "twenty-one million, nine hundred seventy-eight thousand, seven hundred fifty-two".