256615487 has 2 divisors, whose sum is σ = 256615488. Its totient is φ = 256615486.

The previous prime is 256615483. The next prime is 256615523. The reversal of 256615487 is 784516652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256615487 - 2² = 256615483 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256615481) 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, 128307743 + 128307744.

It is an arithmetic number, because the mean of its divisors is an integer number (128307744).

Almost surely, 2^256615487 is an apocalyptic number.

256615487 is a deficient number, since it is larger than the sum of its proper divisors (1).

256615487 is an equidigital number, since it uses as much as digits as its factorization.

256615487 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 403200, while the sum is 44.

The square root of 256615487 is about 16019.2224218281. Note that the first 3 decimals coincide. The cubic root of 256615487 is about 635.4688805544.

The spelling of 256615487 in words is "two hundred fifty-six million, six hundred fifteen thousand, four hundred eighty-seven".