256399787 has 8 divisors (see below), whose sum is σ = 294088416. Its totient is φ = 218976192.

The previous prime is 256399783. The next prime is 256399799. The reversal of 256399787 is 787993652.

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 256399787 - 2² = 256399783 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256399783) 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, 64178 + ... + 68055.

It is an arithmetic number, because the mean of its divisors is an integer number (36761052).

Almost surely, 2^256399787 is an apocalyptic number.

256399787 is a deficient number, since it is larger than the sum of its proper divisors (37688629).

256399787 is a wasteful number, since it uses less digits than its factorization.

256399787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132517.

The product of its digits is 5715360, while the sum is 56.

The square root of 256399787 is about 16012.4884699412. The cubic root of 256399787 is about 635.2907813259.

The spelling of 256399787 in words is "two hundred fifty-six million, three hundred ninety-nine thousand, seven hundred eighty-seven".