21982500 has 90 divisors (see below), whose sum is σ = 69507438. Its totient is φ = 5856000.

The previous prime is 21982489. The next prime is 21982517. The reversal of 21982500 is 528912.

It can be written as a sum of positive squares in 5 ways, for example, as 3526884 + 18455616 = 1878^2 + 4296^2 .

It is a tau number, because it is divible by the number of its divisors (90).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 22012 + ... + 22988.

Almost surely, 2^21982500 is an apocalyptic number.

21982500 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 21982500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34753719).

21982500 is an abundant number, since it is smaller than the sum of its proper divisors (47524938).

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

21982500 is a wasteful number, since it uses less digits than its factorization.

21982500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1007 (or 987 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 21982500 is about 4688.5498824263. The cubic root of 21982500 is about 280.1296168596.

The spelling of 21982500 in words is "twenty-one million, nine hundred eighty-two thousand, five hundred".