11681987 has 4 divisors (see below), whose sum is σ = 11713680. Its totient is φ = 11650296.

The previous prime is 11681981. The next prime is 11682023. The reversal of 11681987 is 78918611.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78918611 = 359 ⋅219829.

It is a cyclic number.

It is not a de Polignac number, because 11681987 - 2⁸ = 11681731 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11681981) 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, 15287 + ... + 16032.

It is an arithmetic number, because the mean of its divisors is an integer number (2928420).

Almost surely, 2^11681987 is an apocalyptic number.

11681987 is a deficient number, since it is larger than the sum of its proper divisors (31693).

11681987 is an equidigital number, since it uses as much as digits as its factorization.

11681987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31692.

The product of its digits is 24192, while the sum is 41.

The square root of 11681987 is about 3417.8921867139. The cubic root of 11681987 is about 226.9023042115.

The spelling of 11681987 in words is "eleven million, six hundred eighty-one thousand, nine hundred eighty-seven".