221653428 has 12 divisors (see below), whose sum is σ = 517191360. Its totient is φ = 73884472.

The previous prime is 221653417. The next prime is 221653447. The reversal of 221653428 is 824356122.

221653428 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9235548 + ... + 9235571.

It is an arithmetic number, because the mean of its divisors is an integer number (43099280).

Almost surely, 2^221653428 is an apocalyptic number.

It is an amenable number.

221653428 is an abundant number, since it is smaller than the sum of its proper divisors (295537932).

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

221653428 is a wasteful number, since it uses less digits than its factorization.

221653428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18471126 (or 18471124 counting only the distinct ones).

The product of its digits is 23040, while the sum is 33.

The square root of 221653428 is about 14888.0296883100. The cubic root of 221653428 is about 605.1896388867.

The spelling of 221653428 in words is "two hundred twenty-one million, six hundred fifty-three thousand, four hundred twenty-eight".