11985661 has 4 divisors (see below), whose sum is σ = 12052800. Its totient is φ = 11918524.

The previous prime is 11985647. The next prime is 11985667. The reversal of 11985661 is 16658911.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11985661 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11985661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11985667) 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, 33301 + ... + 33658.

It is an arithmetic number, because the mean of its divisors is an integer number (3013200).

Almost surely, 2^11985661 is an apocalyptic number.

It is an amenable number.

11985661 is a deficient number, since it is larger than the sum of its proper divisors (67139).

11985661 is an equidigital number, since it uses as much as digits as its factorization.

11985661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67138.

The product of its digits is 12960, while the sum is 37.

The square root of 11985661 is about 3462.0313401239. The cubic root of 11985661 is about 228.8516229569.

It can be divided in two parts, 1198 and 5661, that added together give a cube (6859 = 19³).

The spelling of 11985661 in words is "eleven million, nine hundred eighty-five thousand, six hundred sixty-one".