1291997 has 4 divisors (see below), whose sum is σ = 1476576. Its totient is φ = 1107420.

The previous prime is 1291991. The next prime is 1291999. The reversal of 1291997 is 7991921.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1291997 - 2¹⁶ = 1226461 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1291997.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92279 + ... + 92292.

It is an arithmetic number, because the mean of its divisors is an integer number (369144).

2^1291997 is an apocalyptic number.

It is an amenable number.

1291997 is a deficient number, since it is larger than the sum of its proper divisors (184579).

1291997 is an equidigital number, since it uses as much as digits as its factorization.

1291997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184578.

The product of its digits is 10206, while the sum is 38.

The square root of 1291997 is about 1136.6604594161. The cubic root of 1291997 is about 108.9148677351.

The spelling of 1291997 in words is "one million, two hundred ninety-one thousand, nine hundred ninety-seven".