221551872 has 72 divisors (see below), whose sum is σ = 600886944. Its totient is φ = 72443904.

The previous prime is 221551859. The next prime is 221551873. The reversal of 221551872 is 278155122.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221551873) 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 7 ways as a sum of consecutive naturals, for example, 37983 + ... + 43425.

It is an arithmetic number, because the mean of its divisors is an integer number (8345652).

Almost surely, 2^221551872 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 221551872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (300443472).

221551872 is an abundant number, since it is smaller than the sum of its proper divisors (379335072).

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

221551872 is an equidigital number, since it uses as much as digits as its factorization.

221551872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5515 (or 5501 counting only the distinct ones).

The product of its digits is 11200, while the sum is 33.

The square root of 221551872 is about 14884.6186380438. The cubic root of 221551872 is about 605.0971972335.

The spelling of 221551872 in words is "two hundred twenty-one million, five hundred fifty-one thousand, eight hundred seventy-two".