21889980 has 96 divisors (see below), whose sum is σ = 77844480. Its totient is φ = 5002560.

The previous prime is 21889963. The next prime is 21889981. The reversal of 21889980 is 8998812.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21889981) 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, 885 + ... + 6675.

It is an arithmetic number, because the mean of its divisors is an integer number (810880).

Almost surely, 2^21889980 is an apocalyptic number.

21889980 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 21889980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38922240).

21889980 is an abundant number, since it is smaller than the sum of its proper divisors (55954500).

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

21889980 is a wasteful number, since it uses less digits than its factorization.

21889980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5816 (or 5808 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 45.

The square root of 21889980 is about 4678.6728887581. The cubic root of 21889980 is about 279.7360608023.

The spelling of 21889980 in words is "twenty-one million, eight hundred eighty-nine thousand, nine hundred eighty".