257561661365487 has 144 divisors (see below), whose sum is σ = 412124363489280. Its totient is φ = 154451751471360.

The previous prime is 257561661365483. The next prime is 257561661365497. The reversal of 257561661365487 is 784563166165752.

257561661365487 is a `hidden beast` number, since 2 + 5 + 7 + 5 + 6 + 1 + 6 + 6 + 136 + 5 + 487 = 666.

It is not a de Polignac number, because 257561661365487 - 2² = 257561661365483 is a prime.

It is a Smith number, since the sum of its digits (72) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257561661365483) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 2989888338 + ... + 2989974480.

Almost surely, 2^{257561661365487} is an apocalyptic number.

257561661365487 is a deficient number, since it is larger than the sum of its proper divisors (154562702123793).

257561661365487 is a wasteful number, since it uses less digits than its factorization.

257561661365487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86454 (or 86390 counting only the distinct ones).

The product of its digits is 1524096000, while the sum is 72.

The spelling of 257561661365487 in words is "two hundred fifty-seven trillion, five hundred sixty-one billion, six hundred sixty-one million, three hundred sixty-five thousand, four hundred eighty-seven".