256545407 has 2 divisors, whose sum is σ = 256545408. Its totient is φ = 256545406.

The previous prime is 256545403. The next prime is 256545409. The reversal of 256545407 is 704545652.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 256545407 - 2² = 256545403 is a prime.

Together with 256545409, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256545403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128272703 + 128272704.

It is an arithmetic number, because the mean of its divisors is an integer number (128272704).

Almost surely, 2^256545407 is an apocalyptic number.

256545407 is a deficient number, since it is larger than the sum of its proper divisors (1).

256545407 is an equidigital number, since it uses as much as digits as its factorization.

256545407 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 168000, while the sum is 38.

The square root of 256545407 is about 16017.0349003803. The cubic root of 256545407 is about 635.4110278318.

The spelling of 256545407 in words is "two hundred fifty-six million, five hundred forty-five thousand, four hundred seven".