256907409 has 16 divisors (see below), whose sum is σ = 373980864. Its totient is φ = 155577600.

The previous prime is 256907407. The next prime is 256907419. The reversal of 256907409 is 904709652.

It is not a de Polignac number, because 256907409 - 2¹ = 256907407 is a prime.

It is not an unprimeable number, because it can be changed into a prime (256907407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55629 + ... + 60069.

It is an arithmetic number, because the mean of its divisors is an integer number (23373804).

Almost surely, 2^256907409 is an apocalyptic number.

It is an amenable number.

256907409 is a deficient number, since it is larger than the sum of its proper divisors (117073455).

256907409 is a wasteful number, since it uses less digits than its factorization.

256907409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6208.

The product of its (nonzero) digits is 136080, while the sum is 42.

The square root of 256907409 is about 16028.3314477833. The cubic root of 256907409 is about 635.7097559197.

The spelling of 256907409 in words is "two hundred fifty-six million, nine hundred seven thousand, four hundred nine".