221641530 has 64 divisors (see below), whose sum is σ = 582311808. Its totient is φ = 53544960.

The previous prime is 221641493. The next prime is 221641549. The reversal of 221641530 is 35146122.

It is a self number, because there is not a number n which added to its sum of digits gives 221641530.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 110214 + ... + 112206.

It is an arithmetic number, because the mean of its divisors is an integer number (9098622).

Almost surely, 2^221641530 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221641530, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (291155904).

221641530 is an abundant number, since it is smaller than the sum of its proper divisors (360670278).

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

221641530 is a wasteful number, since it uses less digits than its factorization.

221641530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2351.

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 221641530 is about 14887.6301001872. The cubic root of 221641530 is about 605.1788101570.

Adding to 221641530 its reverse (35146122), we get a palindrome (256787652).

The spelling of 221641530 in words is "two hundred twenty-one million, six hundred forty-one thousand, five hundred thirty".