1278115664 has 40 divisors (see below), whose sum is σ = 2836419648. Its totient is φ = 546543360.

The previous prime is 1278115627. The next prime is 1278115823. The reversal of 1278115664 is 4665118721.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38699 + ... + 63669.

Almost surely, 2^1278115664 is an apocalyptic number.

1278115664 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

1278115664 is an abundant number, since it is smaller than the sum of its proper divisors (1558303984).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1278115664 is a wasteful number, since it uses less digits than its factorization.

1278115664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25443 (or 25437 counting only the distinct ones).

The product of its digits is 80640, while the sum is 41.

The square root of 1278115664 is about 35750.7435447153. The cubic root of 1278115664 is about 1085.2339855107.

The spelling of 1278115664 in words is "one billion, two hundred seventy-eight million, one hundred fifteen thousand, six hundred sixty-four".