1090991 has 4 divisors (see below), whose sum is σ = 1190184. Its totient is φ = 991800.

The previous prime is 1090979. The next prime is 1090997. The reversal of 1090991 is 1990901.

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

It is a cyclic number.

It is not a de Polignac number, because 1090991 - 2⁶ = 1090927 is a prime.

It is a super-2 number, since 2×1090991² = 2380522724162, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1090997) 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, 49580 + ... + 49601.

It is an arithmetic number, because the mean of its divisors is an integer number (297546).

2^1090991 is an apocalyptic number.

1090991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1090991 is a deficient number, since it is larger than the sum of its proper divisors (99193).

1090991 is an equidigital number, since it uses as much as digits as its factorization.

1090991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99192.

The product of its (nonzero) digits is 729, while the sum is 29.

The square root of 1090991 is about 1044.5051459902. The cubic root of 1090991 is about 102.9454262063.

The spelling of 1090991 in words is "one million, ninety thousand, nine hundred ninety-one".