256420609 has 4 divisors (see below), whose sum is σ = 256467904. Its totient is φ = 256373316.

The previous prime is 256420607. The next prime is 256420613. The reversal of 256420609 is 906024652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 256420609 - 2¹ = 256420607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256420607) 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, 14277 + ... + 26770.

It is an arithmetic number, because the mean of its divisors is an integer number (64116976).

Almost surely, 2^256420609 is an apocalyptic number.

It is an amenable number.

256420609 is a deficient number, since it is larger than the sum of its proper divisors (47295).

256420609 is an equidigital number, since it uses as much as digits as its factorization.

256420609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47294.

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 256420609 is about 16013.1386367570. The cubic root of 256420609 is about 635.3079779947.

The spelling of 256420609 in words is "two hundred fifty-six million, four hundred twenty thousand, six hundred nine".