1291463978 has 16 divisors (see below), whose sum is σ = 2265426240. Its totient is φ = 540612576.

The previous prime is 1291463969. The next prime is 1291464019. The reversal of 1291463978 is 8793641921.

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, 1072043 + ... + 1073246.

It is an arithmetic number, because the mean of its divisors is an integer number (141589140).

Almost surely, 2^1291463978 is an apocalyptic number.

1291463978 is a deficient number, since it is larger than the sum of its proper divisors (973962262).

1291463978 is a wasteful number, since it uses less digits than its factorization.

1291463978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2145341.

The product of its digits is 653184, while the sum is 50.

The square root of 1291463978 is about 35936.9444722280. The cubic root of 1291463978 is about 1088.9988782265.

The spelling of 1291463978 in words is "one billion, two hundred ninety-one million, four hundred sixty-three thousand, nine hundred seventy-eight".