1691155 has 4 divisors (see below), whose sum is σ = 2029392. Its totient is φ = 1352920.

The previous prime is 1691141. The next prime is 1691161. The reversal of 1691155 is 5511961.

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

It is not a de Polignac number, because 1691155 - 2¹⁵ = 1658387 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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, 169111 + ... + 169120.

It is an arithmetic number, because the mean of its divisors is an integer number (507348).

2^1691155 is an apocalyptic number.

1691155 is a deficient number, since it is larger than the sum of its proper divisors (338237).

1691155 is an equidigital number, since it uses as much as digits as its factorization.

1691155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338236.

The product of its digits is 1350, while the sum is 28.

The square root of 1691155 is about 1300.4441548948. Note that the first 3 decimals coincide. The cubic root of 1691155 is about 119.1409717422.

The spelling of 1691155 in words is "one million, six hundred ninety-one thousand, one hundred fifty-five".