256622221 has 8 divisors (see below), whose sum is σ = 258030080. Its totient is φ = 255218688.

The previous prime is 256622207. The next prime is 256622231. The reversal of 256622221 is 122226652.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256622221 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 256622221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256622231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 235540 + ... + 236626.

It is an arithmetic number, because the mean of its divisors is an integer number (32253760).

Almost surely, 2^256622221 is an apocalyptic number.

It is an amenable number.

256622221 is a deficient number, since it is larger than the sum of its proper divisors (1407859).

256622221 is a wasteful number, since it uses less digits than its factorization.

256622221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2163.

The product of its digits is 5760, while the sum is 28.

The square root of 256622221 is about 16019.4326054327. The cubic root of 256622221 is about 635.4744390784.

Adding to 256622221 its reverse (122226652), we get a palindrome (378848873).

The spelling of 256622221 in words is "two hundred fifty-six million, six hundred twenty-two thousand, two hundred twenty-one".