256121003 has 4 divisors (see below), whose sum is σ = 256168968. Its totient is φ = 256073040.

The previous prime is 256120981. The next prime is 256121023. The reversal of 256121003 is 300121652.

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 256121003 - 2¹² = 256116907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256121023) by changing a digit.

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, 14801 + ... + 27042.

It is an arithmetic number, because the mean of its divisors is an integer number (64042242).

Almost surely, 2^256121003 is an apocalyptic number.

256121003 is a deficient number, since it is larger than the sum of its proper divisors (47965).

256121003 is an equidigital number, since it uses as much as digits as its factorization.

256121003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47964.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 256121003 is about 16003.7808970256. The cubic root of 256121003 is about 635.0604468467.

Adding to 256121003 its reverse (300121652), we get a palindrome (556242655).

The spelling of 256121003 in words is "two hundred fifty-six million, one hundred twenty-one thousand, three".