21985600 has 168 divisors, whose sum is σ = 67023488. Its totient is φ = 6912000.

The previous prime is 21985597. The next prime is 21985609. The reversal of 21985600 is 658912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21985609) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 145525 + ... + 145675.

Almost surely, 2^21985600 is an apocalyptic number.

21985600 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 21985600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33511744).

21985600 is an abundant number, since it is smaller than the sum of its proper divisors (45037888).

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

21985600 is a wasteful number, since it uses less digits than its factorization.

21985600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193 (or 178 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 21985600 is about 4688.8804633942. The cubic root of 21985600 is about 280.1427843185.

The spelling of 21985600 in words is "twenty-one million, nine hundred eighty-five thousand, six hundred".