1091651 has 4 divisors (see below), whose sum is σ = 1190904. Its totient is φ = 992400.

The previous prime is 1091639. The next prime is 1091659. The reversal of 1091651 is 1561901.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1561901 = 11 ⋅141991.

It is a cyclic number.

It is not a de Polignac number, because 1091651 - 2¹⁰ = 1090627 is a prime.

It is a plaindrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (1091659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49610 + ... + 49631.

It is an arithmetic number, because the mean of its divisors is an integer number (297726).

2^1091651 is an apocalyptic number.

1091651 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1091651 is a deficient number, since it is larger than the sum of its proper divisors (99253).

1091651 is an equidigital number, since it uses as much as digits as its factorization.

1091651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99252.

The product of its (nonzero) digits is 270, while the sum is 23.

The square root of 1091651 is about 1044.8210373073. The cubic root of 1091651 is about 102.9661811239.

The spelling of 1091651 in words is "one million, ninety-one thousand, six hundred fifty-one".