21988230 has 64 divisors (see below), whose sum is σ = 60092928. Its totient is φ = 5096960.

The previous prime is 21988229. The next prime is 21988231. The reversal of 21988230 is 3288912.

It is an interprime number because it is at equal distance from previous prime (21988229) and next prime (21988231).

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 21988191 and 21988200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21988231) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6142 + ... + 9038.

It is an arithmetic number, because the mean of its divisors is an integer number (938952).

Almost surely, 2^21988230 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21988230, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30046464).

21988230 is an abundant number, since it is smaller than the sum of its proper divisors (38104698).

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

21988230 is a wasteful number, since it uses less digits than its factorization.

21988230 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2941.

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 21988230 is about 4689.1609057485. The cubic root of 21988230 is about 280.1539544502.

It can be divided in two parts, 219882 and 30, that added together give a palindrome (219912).

The spelling of 21988230 in words is "twenty-one million, nine hundred eighty-eight thousand, two hundred thirty".