256668999 has 8 divisors (see below), whose sum is σ = 342348672. Its totient is φ = 171051000.

The previous prime is 256668989. The next prime is 256669013. The reversal of 256668999 is 999866652.

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

It is not a de Polignac number, because 256668999 - 2²¹ = 254571847 is a prime.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256668989) 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, 4627 + ... + 23124.

It is an arithmetic number, because the mean of its divisors is an integer number (42793584).

Almost surely, 2^256668999 is an apocalyptic number.

256668999 is a deficient number, since it is larger than the sum of its proper divisors (85679673).

256668999 is a wasteful number, since it uses less digits than its factorization.

256668999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30837.

The product of its digits is 12597120, while the sum is 60.

The square root of 256668999 is about 16020.8925781306. The cubic root of 256668999 is about 635.5130489036.

The spelling of 256668999 in words is "two hundred fifty-six million, six hundred sixty-eight thousand, nine hundred ninety-nine".