12090991 has 4 divisors (see below), whose sum is σ = 13190184. Its totient is φ = 10991800.

The previous prime is 12090983. The next prime is 12090997. The reversal of 12090991 is 19909021.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19909021 = 11 ⋅1809911.

It is a cyclic number.

It is not a de Polignac number, because 12090991 - 2³ = 12090983 is a prime.

It is a super-3 number, since 3×12090991³ (a number of 22 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax 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 (12090997) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 549580 + ... + 549601.

It is an arithmetic number, because the mean of its divisors is an integer number (3297546).

Almost surely, 2^12090991 is an apocalyptic number.

12090991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

12090991 is a deficient number, since it is larger than the sum of its proper divisors (1099193).

12090991 is a wasteful number, since it uses less digits than its factorization.

12090991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1099192.

The product of its (nonzero) digits is 1458, while the sum is 31.

The square root of 12090991 is about 3477.2102323558. The cubic root of 12090991 is about 229.5200514723.

The spelling of 12090991 in words is "twelve million, ninety thousand, nine hundred ninety-one".