221100645 has 32 divisors (see below), whose sum is σ = 358225920. Its totient is φ = 116444160.

The previous prime is 221100637. The next prime is 221100647. The reversal of 221100645 is 546001122.

It is not a de Polignac number, because 221100645 - 2³ = 221100637 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221100647) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 655917 + ... + 656253.

It is an arithmetic number, because the mean of its divisors is an integer number (11194560).

Almost surely, 2^221100645 is an apocalyptic number.

It is an amenable number.

221100645 is a deficient number, since it is larger than the sum of its proper divisors (137125275).

221100645 is a wasteful number, since it uses less digits than its factorization.

221100645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 765.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 221100645 is about 14869.4534196789. The cubic root of 221100645 is about 604.6861245554.

Adding to 221100645 its reverse (546001122), we get a palindrome (767101767).

The spelling of 221100645 in words is "two hundred twenty-one million, one hundred thousand, six hundred forty-five".