221731648 has 56 divisors (see below), whose sum is σ = 452628000. Its totient is φ = 107727360.

The previous prime is 221731613. The next prime is 221731667. The reversal of 221731648 is 846137122.

221731648 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 7 ways as a sum of consecutive naturals, for example, 444103 + ... + 444601.

Almost surely, 2^221731648 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 221731648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (226314000).

221731648 is an abundant number, since it is smaller than the sum of its proper divisors (230896352).

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

221731648 is a wasteful number, since it uses less digits than its factorization.

221731648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 695 (or 685 counting only the distinct ones).

The product of its digits is 16128, while the sum is 34.

The square root of 221731648 is about 14890.6563992324. The cubic root of 221731648 is about 605.2608196284.

The spelling of 221731648 in words is "two hundred twenty-one million, seven hundred thirty-one thousand, six hundred forty-eight".