1266831778 has 12 divisors (see below), whose sum is σ = 1904438610. Its totient is φ = 632021600.

The previous prime is 1266831767. The next prime is 1266831791. The reversal of 1266831778 is 8771386621.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 1225910169 + 40921609 = 35013^2 + 6397^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 982158 + ... + 983446.

Almost surely, 2^1266831778 is an apocalyptic number.

1266831778 is a deficient number, since it is larger than the sum of its proper divisors (637606832).

1266831778 is an frugal number, since it uses more digits than its factorization.

1266831778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2693 (or 1992 counting only the distinct ones).

The product of its digits is 677376, while the sum is 49.

The square root of 1266831778 is about 35592.5803785002. The cubic root of 1266831778 is about 1082.0308660588.

The spelling of 1266831778 in words is "one billion, two hundred sixty-six million, eight hundred thirty-one thousand, seven hundred seventy-eight".