11639681 has 2 divisors, whose sum is σ = 11639682. Its totient is φ = 11639680.

The previous prime is 11639659. The next prime is 11639707. The reversal of 11639681 is 18693611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6760000 + 4879681 = 2600^2 + 2209^2 .

It is a cyclic number.

It is not a de Polignac number, because 11639681 - 2²² = 7445377 is a prime.

It is a super-2 number, since 2×11639681² = 270964347563522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (11639581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5819840 + 5819841.

It is an arithmetic number, because the mean of its divisors is an integer number (5819841).

Almost surely, 2^11639681 is an apocalyptic number.

It is an amenable number.

11639681 is a deficient number, since it is larger than the sum of its proper divisors (1).

11639681 is an equidigital number, since it uses as much as digits as its factorization.

11639681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 35.

The square root of 11639681 is about 3411.6976712481. The cubic root of 11639681 is about 226.6280660431.

The spelling of 11639681 in words is "eleven million, six hundred thirty-nine thousand, six hundred eighty-one".