11981387 has 4 divisors (see below), whose sum is σ = 13070616. Its totient is φ = 10892160.

The previous prime is 11981363. The next prime is 11981393. The reversal of 11981387 is 78318911.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78318911 = 11 ⋅7119901.

It is a cyclic number.

It is not a de Polignac number, because 11981387 - 2⁸ = 11981131 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11981387.

It is not an unprimeable number, because it can be changed into a prime (11981317) 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, 544598 + ... + 544619.

It is an arithmetic number, because the mean of its divisors is an integer number (3267654).

Almost surely, 2^11981387 is an apocalyptic number.

11981387 is a deficient number, since it is larger than the sum of its proper divisors (1089229).

11981387 is a wasteful number, since it uses less digits than its factorization.

11981387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1089228.

The product of its digits is 12096, while the sum is 38.

The square root of 11981387 is about 3461.4140174212. The cubic root of 11981387 is about 228.8244174452.

The spelling of 11981387 in words is "eleven million, nine hundred eighty-one thousand, three hundred eighty-seven".