221985400 has 96 divisors (see below), whose sum is σ = 635271840. Its totient is φ = 70248960.

The previous prime is 221985383. The next prime is 221985403. The reversal of 221985400 is 4589122.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221985403) 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, 12102 + ... + 24298.

It is an arithmetic number, because the mean of its divisors is an integer number (6617415).

Almost surely, 2^221985400 is an apocalyptic number.

221985400 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 221985400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (317635920).

221985400 is an abundant number, since it is smaller than the sum of its proper divisors (413286440).

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

221985400 is a wasteful number, since it uses less digits than its factorization.

221985400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12233 (or 12224 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 221985400 is about 14899.1744737754. The cubic root of 221985400 is about 605.4916205291.

The spelling of 221985400 in words is "two hundred twenty-one million, nine hundred eighty-five thousand, four hundred".