21898400 has 72 divisors (see below), whose sum is σ = 55246464. Its totient is φ = 8467200.

The previous prime is 21898399. The next prime is 21898403. The reversal of 21898400 is 489812.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (21898403) 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, 24359 + ... + 25241.

It is an arithmetic number, because the mean of its divisors is an integer number (767312).

Almost surely, 2^21898400 is an apocalyptic number.

21898400 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 21898400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27623232).

21898400 is an abundant number, since it is smaller than the sum of its proper divisors (33348064).

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

21898400 is a wasteful number, since it uses less digits than its factorization.

21898400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 934 (or 921 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 21898400 is about 4679.5726300593. The cubic root of 21898400 is about 279.7719231116.

The spelling of 21898400 in words is "twenty-one million, eight hundred ninety-eight thousand, four hundred".