256003421 has 4 divisors (see below), whose sum is σ = 258269052. Its totient is φ = 253737792.

The previous prime is 256003417. The next prime is 256003439. The reversal of 256003421 is 124300652.

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

It can be written as a sum of positive squares in 2 ways, for example, as 109956196 + 146047225 = 10486^2 + 12085^2 .

It is a cyclic number.

It is not a de Polignac number, because 256003421 - 2² = 256003417 is a prime.

It is a super-3 number, since 3×256003421³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256003441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1132646 + ... + 1132871.

It is an arithmetic number, because the mean of its divisors is an integer number (64567263).

Almost surely, 2^256003421 is an apocalyptic number.

It is an amenable number.

256003421 is a deficient number, since it is larger than the sum of its proper divisors (2265631).

256003421 is a wasteful number, since it uses less digits than its factorization.

256003421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2265630.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 256003421 is about 16000.1069058928. The cubic root of 256003421 is about 634.9632491596.

The spelling of 256003421 in words is "two hundred fifty-six million, three thousand, four hundred twenty-one".