221840730 has 24 divisors (see below), whose sum is σ = 576786132. Its totient is φ = 59157504.

The previous prime is 221840719. The next prime is 221840737. The reversal of 221840730 is 37048122.

221840730 is a `hidden beast` number, since 221 + 8 + 407 + 30 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 204175521 + 17665209 = 14289^2 + 4203^2 .

It is a junction number, because it is equal to n+sod(n) for n = 221840694 and 221840703.

It is not an unprimeable number, because it can be changed into a prime (221840737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1232359 + ... + 1232538.

Almost surely, 2^221840730 is an apocalyptic number.

221840730 is an abundant number, since it is smaller than the sum of its proper divisors (354945402).

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

221840730 is a wasteful number, since it uses less digits than its factorization.

221840730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2464910 (or 2464907 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 221840730 is about 14894.3187155371. The cubic root of 221840730 is about 605.3600570587.

Adding to 221840730 its reverse (37048122), we get a palindrome (258888852).

The spelling of 221840730 in words is "two hundred twenty-one million, eight hundred forty thousand, seven hundred thirty".