1255785805 has 4 divisors (see below), whose sum is σ = 1506942972. Its totient is φ = 1004628640.

The previous prime is 1255785743. The next prime is 1255785827. The reversal of 1255785805 is 5085875521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5085875521 = 19 ⋅267677659.

It can be written as a sum of positive squares in 2 ways, for example, as 222934761 + 1032851044 = 14931^2 + 32138^2 .

It is not a de Polignac number, because 1255785805 - 2²³ = 1247397197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 125578576 + ... + 125578585.

It is an arithmetic number, because the mean of its divisors is an integer number (376735743).

Almost surely, 2^1255785805 is an apocalyptic number.

It is an amenable number.

1255785805 is a deficient number, since it is larger than the sum of its proper divisors (251157167).

1255785805 is an equidigital number, since it uses as much as digits as its factorization.

1255785805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251157166.

The product of its (nonzero) digits is 560000, while the sum is 46.

The square root of 1255785805 is about 35437.0682337013. The cubic root of 1255785805 is about 1078.8768058259.

The spelling of 1255785805 in words is "one billion, two hundred fifty-five million, seven hundred eighty-five thousand, eight hundred five".