1278181349 has 2 divisors, whose sum is σ = 1278181350. Its totient is φ = 1278181348.

The previous prime is 1278181301. The next prime is 1278181417. The reversal of 1278181349 is 9431818721.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 964537249 + 313644100 = 31057^2 + 17710^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1278181349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1278181049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639090674 + 639090675.

It is an arithmetic number, because the mean of its divisors is an integer number (639090675).

Almost surely, 2^1278181349 is an apocalyptic number.

It is an amenable number.

1278181349 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278181349 is an equidigital number, since it uses as much as digits as its factorization.

1278181349 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96768, while the sum is 44.

The square root of 1278181349 is about 35751.6621851348. The cubic root of 1278181349 is about 1085.2525759965.

The spelling of 1278181349 in words is "one billion, two hundred seventy-eight million, one hundred eighty-one thousand, three hundred forty-nine".