221956 has 12 divisors (see below), whose sum is σ = 443968. Its totient is φ = 95112.

The previous prime is 221953. The next prime is 221957. The reversal of 221956 is 659122.

221956 is an admirable number.

It is a nialpdrome in base 12.

It is a self number, because there is not a number n which added to its sum of digits gives 221956.

It is not an unprimeable number, because it can be changed into a prime (221951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3936 + ... + 3991.

2²²¹⁹⁵⁶ is an apocalyptic number.

It is an amenable number.

221956 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221956 is a wasteful number, since it uses less digits than its factorization.

221956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7938 (or 7936 counting only the distinct ones).

The product of its digits is 1080, while the sum is 25.

The square root of 221956 is about 471.1220648622. The cubic root of 221956 is about 60.5464888682.

It can be divided in two parts, 22195 and 6, that added together give a square (22201 = 149²).

The spelling of 221956 in words is "two hundred twenty-one thousand, nine hundred fifty-six".