1091557 has 4 divisors (see below), whose sum is σ = 1139040. Its totient is φ = 1044076.

The previous prime is 1091551. The next prime is 1091561. The reversal of 1091557 is 7551901.

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 1091557 - 2³ = 1091549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1091551) 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 3 ways as a sum of consecutive naturals, for example, 23707 + ... + 23752.

It is an arithmetic number, because the mean of its divisors is an integer number (284760).

2^1091557 is an apocalyptic number.

It is an amenable number.

1091557 is a deficient number, since it is larger than the sum of its proper divisors (47483).

1091557 is an equidigital number, since it uses as much as digits as its factorization.

1091557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47482.

The product of its (nonzero) digits is 1575, while the sum is 28.

The square root of 1091557 is about 1044.7760525586. The cubic root of 1091557 is about 102.9632256315.

The spelling of 1091557 in words is "one million, ninety-one thousand, five hundred fifty-seven".