21998430 has 48 divisors (see below), whose sum is σ = 58148064. Its totient is φ = 5768640.

The previous prime is 21998423. The next prime is 21998453. The reversal of 21998430 is 3489912.

21998430 is a `hidden beast` number, since 219 + 9 + 8 + 430 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3487 + ... + 7493.

It is an arithmetic number, because the mean of its divisors is an integer number (1211418).

Almost surely, 2^21998430 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21998430, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29074032).

21998430 is an abundant number, since it is smaller than the sum of its proper divisors (36149634).

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

21998430 is a wasteful number, since it uses less digits than its factorization.

21998430 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4081 (or 4078 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 21998430 is about 4690.2483942751. The cubic root of 21998430 is about 280.1972674498.

The spelling of 21998430 in words is "twenty-one million, nine hundred ninety-eight thousand, four hundred thirty".