221306456 has 48 divisors (see below), whose sum is σ = 484803600. Its totient is φ = 92775744.

The previous prime is 221306443. The next prime is 221306461. The reversal of 221306456 is 654603122.

221306456 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 an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 122810 + ... + 124598.

It is an arithmetic number, because the mean of its divisors is an integer number (10100075).

Almost surely, 2^221306456 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 221306456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (242401800).

221306456 is an abundant number, since it is smaller than the sum of its proper divisors (263497144).

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

221306456 is a wasteful number, since it uses less digits than its factorization.

221306456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1896 (or 1845 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 29.

The square root of 221306456 is about 14876.3724072773. The cubic root of 221306456 is about 604.8736899074.

Adding to 221306456 its reverse (654603122), we get a palindrome (875909578).

The spelling of 221306456 in words is "two hundred twenty-one million, three hundred six thousand, four hundred fifty-six".