221897256 has 128 divisors (see below), whose sum is σ = 661340160. Its totient is φ = 60710400.

The previous prime is 221897231. The next prime is 221897323. The reversal of 221897256 is 652798122.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 713341 + ... + 713651.

It is an arithmetic number, because the mean of its divisors is an integer number (5166720).

Almost surely, 2^221897256 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 221897256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (330670080).

221897256 is an abundant number, since it is smaller than the sum of its proper divisors (439442904).

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

221897256 is a wasteful number, since it uses less digits than its factorization.

221897256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495 (or 491 counting only the distinct ones).

The product of its digits is 120960, while the sum is 42.

The square root of 221897256 is about 14896.2161638451. The cubic root of 221897256 is about 605.4114688331.

The spelling of 221897256 in words is "two hundred twenty-one million, eight hundred ninety-seven thousand, two hundred fifty-six".