21998250 has 64 divisors (see below), whose sum is σ = 61027200. Its totient is φ = 5864400.

The previous prime is 21998243. The next prime is 21998267. The reversal of 21998250 is 5289912.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5121 + ... + 8379.

It is an arithmetic number, because the mean of its divisors is an integer number (953550).

Almost surely, 2^21998250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21998250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30513600).

21998250 is an abundant number, since it is smaller than the sum of its proper divisors (39028950).

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

21998250 is a wasteful number, since it uses less digits than its factorization.

21998250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3285 (or 3269 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 21998250 is about 4690.2292054867. The cubic root of 21998250 is about 280.1965032188.

The spelling of 21998250 in words is "twenty-one million, nine hundred ninety-eight thousand, two hundred fifty".