1091918 has 4 divisors (see below), whose sum is σ = 1637880. Its totient is φ = 545958.

The previous prime is 1091917. The next prime is 1091939. The reversal of 1091918 is 8191901.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8191901 = 151 ⋅54251.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1091917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 272978 + ... + 272981.

It is an arithmetic number, because the mean of its divisors is an integer number (409470).

2^1091918 is an apocalyptic number.

1091918 is a deficient number, since it is larger than the sum of its proper divisors (545962).

1091918 is an equidigital number, since it uses as much as digits as its factorization.

1091918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 545961.

The product of its (nonzero) digits is 648, while the sum is 29.

The square root of 1091918 is about 1044.9488025736. The cubic root of 1091918 is about 102.9745750548.

The spelling of 1091918 in words is "one million, ninety-one thousand, nine hundred eighteen".