1091555 has 8 divisors (see below), whose sum is σ = 1340592. Its totient is φ = 852768.

The previous prime is 1091551. The next prime is 1091561. The reversal of 1091555 is 5551901.

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 1091555 - 2² = 1091551 is a prime.

It is a Duffinian 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 7 ways as a sum of consecutive naturals, for example, 2324 + ... + 2753.

It is an arithmetic number, because the mean of its divisors is an integer number (167574).

2^1091555 is an apocalyptic number.

1091555 is a deficient number, since it is larger than the sum of its proper divisors (249037).

1091555 is an equidigital number, since it uses as much as digits as its factorization.

1091555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5125.

The product of its (nonzero) digits is 1125, while the sum is 26.

The square root of 1091555 is about 1044.7750954153. The cubic root of 1091555 is about 102.9631627468.

The spelling of 1091555 in words is "one million, ninety-one thousand, five hundred fifty-five".