21919800 has 192 divisors, whose sum is σ = 82494720. Its totient is φ = 4700160.

The previous prime is 21919771. The next prime is 21919811. The reversal of 21919800 is 891912.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 71247 + ... + 71553.

It is an arithmetic number, because the mean of its divisors is an integer number (429660).

Almost surely, 2^21919800 is an apocalyptic number.

21919800 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 21919800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41247360).

21919800 is an abundant number, since it is smaller than the sum of its proper divisors (60574920).

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

21919800 is a wasteful number, since it uses less digits than its factorization.

21919800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 350 (or 341 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 21919800 is about 4681.8586052977. The cubic root of 21919800 is about 279.8630282445.

The spelling of 21919800 in words is "twenty-one million, nine hundred nineteen thousand, eight hundred".