1278162811 has 4 divisors (see below), whose sum is σ = 1278263272. Its totient is φ = 1278062352.

The previous prime is 1278162761. The next prime is 1278162857. The reversal of 1278162811 is 1182618721.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1182618721 = 31 ⋅38148991.

It is a cyclic number.

It is not a de Polignac number, because 1278162811 - 2¹⁷ = 1278031739 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1278162311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27810 + ... + 57703.

It is an arithmetic number, because the mean of its divisors is an integer number (319565818).

Almost surely, 2^1278162811 is an apocalyptic number.

1278162811 is a deficient number, since it is larger than the sum of its proper divisors (100461).

1278162811 is an equidigital number, since it uses as much as digits as its factorization.

1278162811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100460.

The product of its digits is 10752, while the sum is 37.

The square root of 1278162811 is about 35751.4029235218. The cubic root of 1278162811 is about 1085.2473293467.

The spelling of 1278162811 in words is "one billion, two hundred seventy-eight million, one hundred sixty-two thousand, eight hundred eleven".