11995515666 has 72 divisors (see below), whose sum is σ = 27144627120. Its totient is φ = 3975388632.

The previous prime is 11995515629. The next prime is 11995515667. The reversal of 11995515666 is 66651559911.

11995515666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (11995515667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2346285 + ... + 2351391.

It is an arithmetic number, because the mean of its divisors is an integer number (377008710).

Almost surely, 2^11995515666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 11995515666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13572313560).

11995515666 is an abundant number, since it is smaller than the sum of its proper divisors (15149111454).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

11995515666 is an frugal number, since it uses more digits than its factorization.

11995515666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5312 (or 5291 counting only the distinct ones).

The product of its digits is 2187000, while the sum is 54.

The spelling of 11995515666 in words is "eleven billion, nine hundred ninety-five million, five hundred fifteen thousand, six hundred sixty-six".