1256132789 has 4 divisors (see below), whose sum is σ = 1259860524. Its totient is φ = 1252405056.

The previous prime is 1256132777. The next prime is 1256132791. The reversal of 1256132789 is 9872316521.

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 297735025 + 958397764 = 17255^2 + 30958^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1256132789 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1256132719) 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, 1863362 + ... + 1864035.

It is an arithmetic number, because the mean of its divisors is an integer number (314965131).

Almost surely, 2^1256132789 is an apocalyptic number.

It is an amenable number.

1256132789 is a deficient number, since it is larger than the sum of its proper divisors (3727735).

1256132789 is an equidigital number, since it uses as much as digits as its factorization.

1256132789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3727734.

The product of its digits is 181440, while the sum is 44.

The square root of 1256132789 is about 35441.9636730247. The cubic root of 1256132789 is about 1078.9761642022.

The spelling of 1256132789 in words is "one billion, two hundred fifty-six million, one hundred thirty-two thousand, seven hundred eighty-nine".