11891778 has 8 divisors (see below), whose sum is σ = 23783568. Its totient is φ = 3963924.

The previous prime is 11891771. The next prime is 11891797. The reversal of 11891778 is 87719811.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

11891778 is an admirable number.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (11891771) 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 3 ways as a sum of consecutive naturals, for example, 990976 + ... + 990987.

It is an arithmetic number, because the mean of its divisors is an integer number (2972946).

Almost surely, 2^11891778 is an apocalyptic number.

11891778 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

11891778 is a wasteful number, since it uses less digits than its factorization.

11891778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1981968.

The product of its digits is 28224, while the sum is 42.

The square root of 11891778 is about 3448.4457368502. The cubic root of 11891778 is about 228.2525287568.

The spelling of 11891778 in words is "eleven million, eight hundred ninety-one thousand, seven hundred seventy-eight".