221856261 has 32 divisors (see below), whose sum is σ = 330075648. Its totient is φ = 131423040.

The previous prime is 221856247. The next prime is 221856277. The reversal of 221856261 is 162658122.

It is not a de Polignac number, because 221856261 - 2⁷ = 221856133 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221856281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 292695 + ... + 293451.

It is an arithmetic number, because the mean of its divisors is an integer number (10314864).

Almost surely, 2^221856261 is an apocalyptic number.

It is an amenable number.

221856261 is a deficient number, since it is larger than the sum of its proper divisors (108219387).

221856261 is a wasteful number, since it uses less digits than its factorization.

221856261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 961.

The product of its digits is 11520, while the sum is 33.

The square root of 221856261 is about 14894.8400797055. The cubic root of 221856261 is about 605.3741837517.

The spelling of 221856261 in words is "two hundred twenty-one million, eight hundred fifty-six thousand, two hundred sixty-one".