1247891 has 4 divisors (see below), whose sum is σ = 1252800. Its totient is φ = 1242984.

The previous prime is 1247881. The next prime is 1247893. The reversal of 1247891 is 1987421.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1987421 = 67 ⋅29663.

It is a cyclic number.

It is not a de Polignac number, because 1247891 - 2¹⁰ = 1246867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1247893) 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, 2051 + ... + 2588.

It is an arithmetic number, because the mean of its divisors is an integer number (313200).

2^1247891 is an apocalyptic number.

1247891 is a deficient number, since it is larger than the sum of its proper divisors (4909).

1247891 is an equidigital number, since it uses as much as digits as its factorization.

1247891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4908.

The product of its digits is 4032, while the sum is 32.

The square root of 1247891 is about 1117.0904171105. The cubic root of 1247891 is about 107.6611176944.

The spelling of 1247891 in words is "one million, two hundred forty-seven thousand, eight hundred ninety-one".