221004661 has 8 divisors (see below), whose sum is σ = 222787584. Its totient is φ = 219226800.

The previous prime is 221004643. The next prime is 221004671. The reversal of 221004661 is 166400122.

221004661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221004661 - 2⁵ = 221004629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221004671) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 180096 + ... + 181318.

It is an arithmetic number, because the mean of its divisors is an integer number (27848448).

Almost surely, 2^221004661 is an apocalyptic number.

It is an amenable number.

221004661 is a deficient number, since it is larger than the sum of its proper divisors (1782923).

221004661 is a wasteful number, since it uses less digits than its factorization.

221004661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2531.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 221004661 is about 14866.2255128866. The cubic root of 221004661 is about 604.5986099700.

Adding to 221004661 its reverse (166400122), we get a palindrome (387404783).

The spelling of 221004661 in words is "two hundred twenty-one million, four thousand, six hundred sixty-one".