1291657 has 8 divisors (see below), whose sum is σ = 1365120. Its totient is φ = 1219680.

The previous prime is 1291637. The next prime is 1291669. The reversal of 1291657 is 7561921.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1291657 - 2¹⁵ = 1258889 is a prime.

It is a Duffinian number.

1291657 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1291637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1732 + ... + 2362.

It is an arithmetic number, because the mean of its divisors is an integer number (170640).

2^1291657 is an apocalyptic number.

It is an amenable number.

1291657 is a deficient number, since it is larger than the sum of its proper divisors (73463).

1291657 is an equidigital number, since it uses as much as digits as its factorization.

1291657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 743.

The product of its digits is 3780, while the sum is 31.

The square root of 1291657 is about 1136.5108886412. The cubic root of 1291657 is about 108.9053129390.

The spelling of 1291657 in words is "one million, two hundred ninety-one thousand, six hundred fifty-seven".