1291897 has 4 divisors (see below), whose sum is σ = 1297296. Its totient is φ = 1286500.

The previous prime is 1291883. The next prime is 1291907. The reversal of 1291897 is 7981921.

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, and also an emirpimes, since its reverse is a distinct semiprime: 7981921 = 41 ⋅194681.

It is a cyclic number.

It is not a de Polignac number, because 1291897 - 2¹⁵ = 1259129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1291817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2323 + ... + 2824.

It is an arithmetic number, because the mean of its divisors is an integer number (324324).

2^1291897 is an apocalyptic number.

It is an amenable number.

1291897 is a deficient number, since it is larger than the sum of its proper divisors (5399).

1291897 is an equidigital number, since it uses as much as digits as its factorization.

1291897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5398.

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

The square root of 1291897 is about 1136.6164700549. The cubic root of 1291897 is about 108.9120576750.

The spelling of 1291897 in words is "one million, two hundred ninety-one thousand, eight hundred ninety-seven".