256815853 has 8 divisors (see below), whose sum is σ = 301436672. Its totient is φ = 214178256.

The previous prime is 256815833. The next prime is 256815857. The reversal of 256815853 is 358518652.

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

It is a cyclic number.

It is not a de Polignac number, because 256815853 - 2¹⁷ = 256684781 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 (256815857) 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, 495525 + ... + 496042.

It is an arithmetic number, because the mean of its divisors is an integer number (37679584).

Almost surely, 2^256815853 is an apocalyptic number.

It is an amenable number.

256815853 is a deficient number, since it is larger than the sum of its proper divisors (44620819).

256815853 is an equidigital number, since it uses as much as digits as its factorization.

256815853 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 991611.

The product of its digits is 288000, while the sum is 43.

The square root of 256815853 is about 16025.4751255618. The cubic root of 256815853 is about 635.6342294124.

The spelling of 256815853 in words is "two hundred fifty-six million, eight hundred fifteen thousand, eight hundred fifty-three".