221664600 has 144 divisors (see below), whose sum is σ = 772164120. Its totient is φ = 59097600.

The previous prime is 221664587. The next prime is 221664607. The reversal of 221664600 is 6466122.

It is a happy number.

221664600 is a `hidden beast` number, since 2 + 2 + 16 + 646 + 0 + 0 = 666.

221664600 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221664607) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 46320 + ... + 50880.

Almost surely, 2^221664600 is an apocalyptic number.

221664600 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 221664600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (386082060).

221664600 is an abundant number, since it is smaller than the sum of its proper divisors (550499520).

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

221664600 is a wasteful number, since it uses less digits than its factorization.

221664600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4592 (or 4571 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 221664600 is about 14888.4048843387. The cubic root of 221664600 is about 605.1998065091.

The spelling of 221664600 in words is "two hundred twenty-one million, six hundred sixty-four thousand, six hundred".