256603387 has 4 divisors (see below), whose sum is σ = 267760080. Its totient is φ = 245446696.

The previous prime is 256603363. The next prime is 256603411. The reversal of 256603387 is 783306652.

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

It is an interprime number because it is at equal distance from previous prime (256603363) and next prime (256603411).

It is a cyclic number.

It is not a de Polignac number, because 256603387 - 2¹⁵ = 256570619 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256603307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5578312 + ... + 5578357.

It is an arithmetic number, because the mean of its divisors is an integer number (66940020).

Almost surely, 2^256603387 is an apocalyptic number.

256603387 is a deficient number, since it is larger than the sum of its proper divisors (11156693).

256603387 is a wasteful number, since it uses less digits than its factorization.

256603387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11156692.

The product of its (nonzero) digits is 181440, while the sum is 40.

The square root of 256603387 is about 16018.8447461108. The cubic root of 256603387 is about 635.4588924662.

The spelling of 256603387 in words is "two hundred fifty-six million, six hundred three thousand, three hundred eighty-seven".