11917121 has 4 divisors (see below), whose sum is σ = 11977812. Its totient is φ = 11856432.

The previous prime is 11917117. The next prime is 11917127. The reversal of 11917121 is 12171911.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12171911 = 1999 ⋅6089.

It can be written as a sum of positive squares in 2 ways, for example, as 11316496 + 600625 = 3364^2 + 775^2 .

It is a cyclic number.

It is not a de Polignac number, because 11917121 - 2² = 11917117 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11917127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30050 + ... + 30443.

It is an arithmetic number, because the mean of its divisors is an integer number (2994453).

Almost surely, 2^11917121 is an apocalyptic number.

It is an amenable number.

11917121 is a deficient number, since it is larger than the sum of its proper divisors (60691).

11917121 is an equidigital number, since it uses as much as digits as its factorization.

11917121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60690.

The product of its digits is 126, while the sum is 23.

The square root of 11917121 is about 3452.1183351676. The cubic root of 11917121 is about 228.4145594595.

The spelling of 11917121 in words is "eleven million, nine hundred seventeen thousand, one hundred twenty-one".