221656261 has 8 divisors (see below), whose sum is σ = 234722880. Its totient is φ = 208729728.

The previous prime is 221656247. The next prime is 221656289. The reversal of 221656261 is 162656122.

221656261 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 a de Polignac number, because none of the positive numbers 2^k-221656261 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 (221656361) 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, 31756 + ... + 38101.

It is an arithmetic number, because the mean of its divisors is an integer number (29340360).

Almost surely, 2^221656261 is an apocalyptic number.

It is an amenable number.

221656261 is a deficient number, since it is larger than the sum of its proper divisors (13066619).

221656261 is a wasteful number, since it uses less digits than its factorization.

221656261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70043.

The product of its digits is 8640, while the sum is 31.

The square root of 221656261 is about 14888.1248315562. The cubic root of 221656261 is about 605.1922172286.

The spelling of 221656261 in words is "two hundred twenty-one million, six hundred fifty-six thousand, two hundred sixty-one".