21989120 has 72 divisors (see below), whose sum is σ = 54084240. Its totient is φ = 8560640.

The previous prime is 21989119. The next prime is 21989129. The reversal of 21989120 is 2198912.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21989129) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52271 + ... + 52689.

It is an arithmetic number, because the mean of its divisors is an integer number (751170).

Almost surely, 2^21989120 is an apocalyptic number.

21989120 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 21989120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27042120).

21989120 is an abundant number, since it is smaller than the sum of its proper divisors (32095120).

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

21989120 is an equidigital number, since it uses as much as digits as its factorization.

21989120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 481 (or 467 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 21989120 is about 4689.2558044961. The cubic root of 21989120 is about 280.1577342551.

The spelling of 21989120 in words is "twenty-one million, nine hundred eighty-nine thousand, one hundred twenty".