221813328 has 120 divisors (see below), whose sum is σ = 636327328. Its totient is φ = 66528000.

The previous prime is 221813327. The next prime is 221813329. The reversal of 221813328 is 823318122.

It is an interprime number because it is at equal distance from previous prime (221813327) and next prime (221813329).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 221813295 and 221813304.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221813323) 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, 1051143 + ... + 1051353.

Almost surely, 2^221813328 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221813328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (318163664).

221813328 is an abundant number, since it is smaller than the sum of its proper divisors (414514000).

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

221813328 is a wasteful number, since it uses less digits than its factorization.

221813328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 425 (or 408 counting only the distinct ones).

The product of its digits is 4608, while the sum is 30.

The square root of 221813328 is about 14893.3988061826. The cubic root of 221813328 is about 605.3351311290.

The spelling of 221813328 in words is "two hundred twenty-one million, eight hundred thirteen thousand, three hundred twenty-eight".