221501730 has 32 divisors (see below), whose sum is σ = 554719104. Its totient is φ = 56498816.

The previous prime is 221501717. The next prime is 221501771. The reversal of 221501730 is 37105122.

221501730 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 221501697 and 221501706.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 159819 + ... + 161198.

It is an arithmetic number, because the mean of its divisors is an integer number (17334972).

Almost surely, 2^221501730 is an apocalyptic number.

221501730 is an abundant number, since it is smaller than the sum of its proper divisors (333217374).

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

221501730 is a wasteful number, since it uses less digits than its factorization.

221501730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321050.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 221501730 is about 14882.9341865104. The cubic root of 221501730 is about 605.0515449105.

Adding to 221501730 its reverse (37105122), we get a palindrome (258606852).

The spelling of 221501730 in words is "two hundred twenty-one million, five hundred one thousand, seven hundred thirty".