221570661 has 24 divisors (see below), whose sum is σ = 333827136. Its totient is φ = 130416000.

The previous prime is 221570617. The next prime is 221570663. The reversal of 221570661 is 166075122.

It is not a de Polignac number, because 221570661 - 2⁶ = 221570597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221570663) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2161 + ... + 21161.

It is an arithmetic number, because the mean of its divisors is an integer number (13909464).

Almost surely, 2^221570661 is an apocalyptic number.

It is an amenable number.

221570661 is a deficient number, since it is larger than the sum of its proper divisors (112256475).

221570661 is a wasteful number, since it uses less digits than its factorization.

221570661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19053 (or 19040 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 221570661 is about 14885.2497795637. The cubic root of 221570661 is about 605.1143021065.

The spelling of 221570661 in words is "two hundred twenty-one million, five hundred seventy thousand, six hundred sixty-one".