1089910991 has 4 divisors (see below), whose sum is σ = 1173750312. Its totient is φ = 1006071672.

The previous prime is 1089910979. The next prime is 1089911023. The reversal of 1089910991 is 1990199801.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1089910991 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 (1089910901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41919641 + ... + 41919666.

It is an arithmetic number, because the mean of its divisors is an integer number (293437578).

Almost surely, 2^1089910991 is an apocalyptic number.

1089910991 is a deficient number, since it is larger than the sum of its proper divisors (83839321).

1089910991 is an equidigital number, since it uses as much as digits as its factorization.

1089910991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83839320.

The product of its (nonzero) digits is 52488, while the sum is 47.

The square root of 1089910991 is about 33013.8000084813. The cubic root of 1089910991 is about 1029.1144526769.

It can be divided in two parts, 1089910 and 991, that added together give a palindrome (1090901).

The spelling of 1089910991 in words is "one billion, eighty-nine million, nine hundred ten thousand, nine hundred ninety-one".