21890232 has 144 divisors (see below), whose sum is σ = 73653840. Its totient is φ = 5750784.

The previous prime is 21890221. The next prime is 21890243. The reversal of 21890232 is 23209812.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21890221) and next prime (21890243).

It is a junction number, because it is equal to n+sod(n) for n = 21890196 and 21890205.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 85048 + ... + 85304.

It is an arithmetic number, because the mean of its divisors is an integer number (511485).

Almost surely, 2^21890232 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21890232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36826920).

21890232 is an abundant number, since it is smaller than the sum of its proper divisors (51763608).

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

21890232 is a wasteful number, since it uses less digits than its factorization.

21890232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302 (or 282 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 21890232 is about 4678.6998193943. The cubic root of 21890232 is about 279.7371342496.

It can be divided in two parts, 21890 and 232, that added together give a palindrome (22122).

The spelling of 21890232 in words is "twenty-one million, eight hundred ninety thousand, two hundred thirty-two".