11981587 has 2 divisors, whose sum is σ = 11981588. Its totient is φ = 11981586.

The previous prime is 11981443. The next prime is 11981603. The reversal of 11981587 is 78518911.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11981587 is a prime.

It is not a weakly prime, because it can be changed into another prime (11981087) 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 as a sum of consecutive naturals, namely, 5990793 + 5990794.

It is an arithmetic number, because the mean of its divisors is an integer number (5990794).

Almost surely, 2^11981587 is an apocalyptic number.

11981587 is a deficient number, since it is larger than the sum of its proper divisors (1).

11981587 is an equidigital number, since it uses as much as digits as its factorization.

11981587 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20160, while the sum is 40.

The square root of 11981587 is about 3461.4429072281. The cubic root of 11981587 is about 228.8256906597.

The spelling of 11981587 in words is "eleven million, nine hundred eighty-one thousand, five hundred eighty-seven".