21750400 has 96 divisors (see below), whose sum is σ = 61469280. Its totient is φ = 7449600.

The previous prime is 21750397. The next prime is 21750403. The reversal of 21750400 is 405712.

It is an interprime number because it is at equal distance from previous prime (21750397) and next prime (21750403).

It is not an unprimeable number, because it can be changed into a prime (21750403) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21915 + ... + 22885.

It is an arithmetic number, because the mean of its divisors is an integer number (640305).

Almost surely, 2^21750400 is an apocalyptic number.

21750400 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 21750400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30734640).

21750400 is an abundant number, since it is smaller than the sum of its proper divisors (39718880).

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

21750400 is an equidigital number, since it uses as much as digits as its factorization.

21750400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1002 (or 985 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 21750400 is about 4663.7324108486. The cubic root of 21750400 is about 279.1402197664.

The spelling of 21750400 in words is "twenty-one million, seven hundred fifty thousand, four hundred".