221300661 has 16 divisors (see below), whose sum is σ = 311674880. Its totient is φ = 139451760.

The previous prime is 221300609. The next prime is 221300689. The reversal of 221300661 is 166003122.

It is a happy number.

It is not a de Polignac number, because 221300661 - 2⁷ = 221300533 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221300461) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23671 + ... + 31668.

It is an arithmetic number, because the mean of its divisors is an integer number (19479680).

Almost surely, 2^221300661 is an apocalyptic number.

It is an amenable number.

221300661 is a deficient number, since it is larger than the sum of its proper divisors (90374219).

221300661 is a wasteful number, since it uses less digits than its factorization.

221300661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55416.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 221300661 is about 14876.1776340564. The cubic root of 221300661 is about 604.8684102397.

Adding to 221300661 its reverse (166003122), we get a palindrome (387303783).

The spelling of 221300661 in words is "two hundred twenty-one million, three hundred thousand, six hundred sixty-one".