256417221 has 8 divisors (see below), whose sum is σ = 347494624. Its totient is φ = 168142320.

The previous prime is 256417211. The next prime is 256417237. The reversal of 256417221 is 122714652.

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

It is not a de Polignac number, because 256417221 - 2¹⁰ = 256416197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256417201) 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, 700411 + ... + 700776.

It is an arithmetic number, because the mean of its divisors is an integer number (43436828).

Almost surely, 2^256417221 is an apocalyptic number.

It is an amenable number.

256417221 is a deficient number, since it is larger than the sum of its proper divisors (91077403).

256417221 is a wasteful number, since it uses less digits than its factorization.

256417221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1401251.

The product of its digits is 6720, while the sum is 30.

The square root of 256417221 is about 16013.0328482771. The cubic root of 256417221 is about 635.3051799448.

The spelling of 256417221 in words is "two hundred fifty-six million, four hundred seventeen thousand, two hundred twenty-one".