1291643 has 4 divisors (see below), whose sum is σ = 1367640. Its totient is φ = 1215648.

The previous prime is 1291637. The next prime is 1291669. The reversal of 1291643 is 3461921.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1291643 - 2⁶ = 1291579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1291603) 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, 37973 + ... + 38006.

It is an arithmetic number, because the mean of its divisors is an integer number (341910).

2^1291643 is an apocalyptic number.

1291643 is a deficient number, since it is larger than the sum of its proper divisors (75997).

1291643 is an equidigital number, since it uses as much as digits as its factorization.

1291643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75996.

The product of its digits is 1296, while the sum is 26.

The square root of 1291643 is about 1136.5047294226. The cubic root of 1291643 is about 108.9049194703.

The spelling of 1291643 in words is "one million, two hundred ninety-one thousand, six hundred forty-three".