20989800 has 288 divisors, whose sum is σ = 81691200. Its totient is φ = 4942080.

The previous prime is 20989799. The next prime is 20989807. The reversal of 20989800 is 898902.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20989807) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 912589 + ... + 912611.

It is an arithmetic number, because the mean of its divisors is an integer number (283650).

Almost surely, 2^20989800 is an apocalyptic number.

20989800 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 20989800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40845600).

20989800 is an abundant number, since it is smaller than the sum of its proper divisors (60701400).

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

20989800 is a wasteful number, since it uses less digits than its factorization.

20989800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74 (or 46 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 20989800 is about 4581.4626485436. The cubic root of 20989800 is about 275.8477421080.

It can be divided in two parts, 209 and 89800, that added together give a palindrome (90009).

The spelling of 20989800 in words is "twenty million, nine hundred eighty-nine thousand, eight hundred".