1256766431 has 4 divisors (see below), whose sum is σ = 1260136152. Its totient is φ = 1253396712.

The previous prime is 1256766397. The next prime is 1256766449. The reversal of 1256766431 is 1346676521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1346676521 = 5147 ⋅261643.

It is a cyclic number.

It is not a de Polignac number, because 1256766431 - 2⁶ = 1256766367 is a prime.

It is a super-2 number, since 2×1256766431² = 3158923724176955522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1256766131) 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, 1684301 + ... + 1685046.

It is an arithmetic number, because the mean of its divisors is an integer number (315034038).

Almost surely, 2^1256766431 is an apocalyptic number.

1256766431 is a deficient number, since it is larger than the sum of its proper divisors (3369721).

1256766431 is an equidigital number, since it uses as much as digits as its factorization.

1256766431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3369720.

The product of its digits is 181440, while the sum is 41.

The square root of 1256766431 is about 35450.9016951614. The cubic root of 1256766431 is about 1079.1575594851.

The spelling of 1256766431 in words is "one billion, two hundred fifty-six million, seven hundred sixty-six thousand, four hundred thirty-one".