221851028 has 48 divisors (see below), whose sum is σ = 457699200. Its totient is φ = 94042368.

The previous prime is 221851027. The next prime is 221851043. The reversal of 221851028 is 820158122.

It is a happy number.

221851028 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221851027) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 132251 + ... + 133917.

It is an arithmetic number, because the mean of its divisors is an integer number (9535400).

Almost surely, 2^221851028 is an apocalyptic number.

221851028 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221851028, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (228849600).

221851028 is an abundant number, since it is smaller than the sum of its proper divisors (235848172).

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

221851028 is a wasteful number, since it uses less digits than its factorization.

221851028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1789 (or 1773 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 29.

The square root of 221851028 is about 14894.6644138094. The cubic root of 221851028 is about 605.3694239912.

The spelling of 221851028 in words is "two hundred twenty-one million, eight hundred fifty-one thousand, twenty-eight".