1291978 has 16 divisors (see below), whose sum is σ = 2018016. Its totient is φ = 619920.

The previous prime is 1291967. The next prime is 1291991. The reversal of 1291978 is 8791921.

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, 7048 + ... + 7228.

It is an arithmetic number, because the mean of its divisors is an integer number (126126).

2^1291978 is an apocalyptic number.

1291978 is a deficient number, since it is larger than the sum of its proper divisors (726038).

1291978 is a wasteful number, since it uses less digits than its factorization.

1291978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309.

The product of its digits is 9072, while the sum is 37.

The square root of 1291978 is about 1136.6521015685. The cubic root of 1291978 is about 108.9143338349.

The spelling of 1291978 in words is "one million, two hundred ninety-one thousand, nine hundred seventy-eight".