11666781 has 16 divisors (see below), whose sum is σ = 19753600. Its totient is φ = 6666624.

The previous prime is 11666749. The next prime is 11666797. The reversal of 11666781 is 18766611.

11666781 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 11666781 - 2⁵ = 11666749 is a prime.

It is a super-2 number, since 2×11666781² = 272227557803922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11666701) 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 in 15 ways as a sum of consecutive naturals, for example, 30676 + ... + 31053.

It is an arithmetic number, because the mean of its divisors is an integer number (1234600).

Almost surely, 2^11666781 is an apocalyptic number.

It is an amenable number.

11666781 is a deficient number, since it is larger than the sum of its proper divisors (8086819).

11666781 is an equidigital number, since it uses as much as digits as its factorization.

11666781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61745 (or 61739 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 11666781 is about 3415.6669919651. Note that the first 3 decimals coincide. The cubic root of 11666781 is about 226.8038114194.

The spelling of 11666781 in words is "eleven million, six hundred sixty-six thousand, seven hundred eighty-one".