256418621 has 4 divisors (see below), whose sum is σ = 263348892. Its totient is φ = 249488352.

The previous prime is 256418593. The next prime is 256418641. The reversal of 256418621 is 126814652.

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 247716121 + 8702500 = 15739^2 + 2950^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256418621 is a prime.

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 (256418641) 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, 3465080 + ... + 3465153.

It is an arithmetic number, because the mean of its divisors is an integer number (65837223).

Almost surely, 2^256418621 is an apocalyptic number.

It is an amenable number.

256418621 is a deficient number, since it is larger than the sum of its proper divisors (6930271).

256418621 is an equidigital number, since it uses as much as digits as its factorization.

256418621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6930270.

The product of its digits is 23040, while the sum is 35.

The square root of 256418621 is about 16013.0765626097. The cubic root of 256418621 is about 635.3063361668.

The spelling of 256418621 in words is "two hundred fifty-six million, four hundred eighteen thousand, six hundred twenty-one".