1278666363 has 16 divisors (see below), whose sum is σ = 1854218016. Its totient is φ = 779078400.

The previous prime is 1278666343. The next prime is 1278666379. The reversal of 1278666363 is 3636668721.

It is a happy number.

It is not a de Polignac number, because 1278666363 - 2¹² = 1278662267 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1278666343) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 158370 + ... + 166247.

It is an arithmetic number, because the mean of its divisors is an integer number (115888626).

Almost surely, 2^1278666363 is an apocalyptic number.

1278666363 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

1278666363 is a deficient number, since it is larger than the sum of its proper divisors (575551653).

1278666363 is a wasteful number, since it uses less digits than its factorization.

1278666363 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324734.

The product of its digits is 1306368, while the sum is 48.

The square root of 1278666363 is about 35758.4446389940. Note that the first 3 decimals coincide. The cubic root of 1278666363 is about 1085.3898272898.

The spelling of 1278666363 in words is "one billion, two hundred seventy-eight million, six hundred sixty-six thousand, three hundred sixty-three".