221405730 has 64 divisors (see below), whose sum is σ = 654006528. Its totient is φ = 46713600.

The previous prime is 221405729. The next prime is 221405741. The reversal of 221405730 is 37504122.

221405730 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 221405730.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 37821 + ... + 43280.

It is an arithmetic number, because the mean of its divisors is an integer number (10218852).

Almost surely, 2^221405730 is an apocalyptic number.

221405730 is an abundant number, since it is smaller than the sum of its proper divisors (432600798).

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

221405730 is a wasteful number, since it uses less digits than its factorization.

221405730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81131.

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 221405730 is about 14879.7086665028. The cubic root of 221405730 is about 604.9641214522.

Adding to 221405730 its reverse (37504122), we get a palindrome (258909852).

The spelling of 221405730 in words is "two hundred twenty-one million, four hundred five thousand, seven hundred thirty".