256415 has 4 divisors (see below), whose sum is σ = 307704. Its totient is φ = 205128.

The previous prime is 256393. The next prime is 256423. The reversal of 256415 is 514652.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 256415 - 2¹² = 252319 is a prime.

It is a Duffinian number.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 25637 + ... + 25646.

It is an arithmetic number, because the mean of its divisors is an integer number (76926).

2²⁵⁶⁴¹⁵ is an apocalyptic number.

256415 is a deficient number, since it is larger than the sum of its proper divisors (51289).

256415 is an equidigital number, since it uses as much as digits as its factorization.

256415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51288.

The product of its digits is 1200, while the sum is 23.

The square root of 256415 is about 506.3743674397. The cubic root of 256415 is about 63.5303345673.

The spelling of 256415 in words is "two hundred fifty-six thousand, four hundred fifteen".