11987681 has 2 divisors, whose sum is σ = 11987682. Its totient is φ = 11987680.

The previous prime is 11987671. The next prime is 11987687. The reversal of 11987681 is 18678911.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10297681 + 1690000 = 3209^2 + 1300^2 .

It is a cyclic number.

It is not a de Polignac number, because 11987681 - 2¹⁸ = 11725537 is a prime.

It is a super-2 number, since 2×11987681² = 287408991515522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (11987687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5993840 + 5993841.

It is an arithmetic number, because the mean of its divisors is an integer number (5993841).

Almost surely, 2^11987681 is an apocalyptic number.

It is an amenable number.

11987681 is a deficient number, since it is larger than the sum of its proper divisors (1).

11987681 is an equidigital number, since it uses as much as digits as its factorization.

11987681 is an evil number, because the sum of its binary digits is even.

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

The square root of 11987681 is about 3462.3230640713. The cubic root of 11987681 is about 228.8644787160.

The spelling of 11987681 in words is "eleven million, nine hundred eighty-seven thousand, six hundred eighty-one".