21859900 has 18 divisors (see below), whose sum is σ = 47436200. Its totient is φ = 8743920.

The previous prime is 21859897. The next prime is 21859907. The reversal of 21859900 is 995812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21859907) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 109200 + ... + 109399.

Almost surely, 2^21859900 is an apocalyptic number.

21859900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21859900 is an abundant number, since it is smaller than the sum of its proper divisors (25576300).

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

21859900 is a wasteful number, since it uses less digits than its factorization.

21859900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218613 (or 218606 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 34.

The square root of 21859900 is about 4675.4571968953. The cubic root of 21859900 is about 279.6078694581.

The spelling of 21859900 in words is "twenty-one million, eight hundred fifty-nine thousand, nine hundred".