11987491 has 4 divisors (see below), whose sum is σ = 12242592. Its totient is φ = 11732392.

The previous prime is 11987489. The next prime is 11987501. The reversal of 11987491 is 19478911.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19478911 = 193 ⋅100927.

It is a cyclic number.

It is not a de Polignac number, because 11987491 - 2¹ = 11987489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11987401) 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, 127480 + ... + 127573.

It is an arithmetic number, because the mean of its divisors is an integer number (3060648).

Almost surely, 2^11987491 is an apocalyptic number.

11987491 is a deficient number, since it is larger than the sum of its proper divisors (255101).

11987491 is an equidigital number, since it uses as much as digits as its factorization.

11987491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255100.

The product of its digits is 18144, while the sum is 40.

The square root of 11987491 is about 3462.2956257374. The cubic root of 11987491 is about 228.8632695725.

The spelling of 11987491 in words is "eleven million, nine hundred eighty-seven thousand, four hundred ninety-one".