11991728 has 20 divisors (see below), whose sum is σ = 26553360. Its totient is φ = 5139264.

The previous prime is 11991719. The next prime is 11991731. The reversal of 11991728 is 82719911.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 11991691 and 11991700.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53423 + ... + 53646.

It is an arithmetic number, because the mean of its divisors is an integer number (1327668).

Almost surely, 2^11991728 is an apocalyptic number.

It is an amenable number.

11991728 is an abundant number, since it is smaller than the sum of its proper divisors (14561632).

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

11991728 is a wasteful number, since it uses less digits than its factorization.

11991728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107084 (or 107078 counting only the distinct ones).

The product of its digits is 9072, while the sum is 38.

The square root of 11991728 is about 3462.9074489510. The cubic root of 11991728 is about 228.8902304394.

The spelling of 11991728 in words is "eleven million, nine hundred ninety-one thousand, seven hundred twenty-eight".