221785956 has 108 divisors (see below), whose sum is σ = 663521040. Its totient is φ = 62264160.

The previous prime is 221785937. The next prime is 221785957. The reversal of 221785956 is 659587122.

221785956 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (221785957) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 103011 + ... + 105141.

Almost surely, 2^221785956 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221785956, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (331760520).

221785956 is an abundant number, since it is smaller than the sum of its proper divisors (441735084).

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

221785956 is a wasteful number, since it uses less digits than its factorization.

221785956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2214 (or 2202 counting only the distinct ones).

The product of its digits is 302400, while the sum is 45.

The square root of 221785956 is about 14892.4798472249. The cubic root of 221785956 is about 605.3102304389.

The spelling of 221785956 in words is "two hundred twenty-one million, seven hundred eighty-five thousand, nine hundred fifty-six".