1266892778 has 4 divisors (see below), whose sum is σ = 1900339170. Its totient is φ = 633446388.

The previous prime is 1266892777. The next prime is 1266892801. The reversal of 1266892778 is 8772986621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8772986621 = 7 ⋅1253283803.

It can be written as a sum of positive squares in only one way, i.e., 1021249849 + 245642929 = 31957^2 + 15673^2 .

It is not an unprimeable number, because it can be changed into a prime (1266892777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 316723193 + ... + 316723196.

Almost surely, 2^1266892778 is an apocalyptic number.

1266892778 is a deficient number, since it is larger than the sum of its proper divisors (633446392).

1266892778 is an equidigital number, since it uses as much as digits as its factorization.

1266892778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 633446391.

The product of its digits is 4064256, while the sum is 56.

The square root of 1266892778 is about 35593.4372883542. The cubic root of 1266892778 is about 1082.0482329591.

The spelling of 1266892778 in words is "one billion, two hundred sixty-six million, eight hundred ninety-two thousand, seven hundred seventy-eight".