257478782809 has 4 divisors (see below), whose sum is σ = 257486657716. Its totient is φ = 257470907904.

The previous prime is 257478782807. The next prime is 257478782819. The reversal of 257478782809 is 908287874752.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 175913136400 + 81565646409 = 419420^2 + 285597^2 .

It is a cyclic number.

It is not a de Polignac number, because 257478782809 - 2¹ = 257478782807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (257478782807) 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, 3888204 + ... + 3953869.

It is an arithmetic number, because the mean of its divisors is an integer number (64371664429).

Almost surely, 2^257478782809 is an apocalyptic number.

It is an amenable number.

257478782809 is a deficient number, since it is larger than the sum of its proper divisors (7874907).

257478782809 is an equidigital number, since it uses as much as digits as its factorization.

257478782809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7874906.

The product of its (nonzero) digits is 126443520, while the sum is 67.

The spelling of 257478782809 in words is "two hundred fifty-seven billion, four hundred seventy-eight million, seven hundred eighty-two thousand, eight hundred nine".