11561778 has 80 divisors (see below), whose sum is σ = 28226880. Its totient is φ = 3525984.

The previous prime is 11561777. The next prime is 11561779. The reversal of 11561778 is 87716511.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (11561777) and next prime (11561779).

It is not an unprimeable number, because it can be changed into a prime (11561777) 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 39 ways as a sum of consecutive naturals, for example, 108001 + ... + 108107.

It is an arithmetic number, because the mean of its divisors is an integer number (352836).

Almost surely, 2^11561778 is an apocalyptic number.

11561778 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 11561778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14113440).

11561778 is an abundant number, since it is smaller than the sum of its proper divisors (16665102).

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

11561778 is a wasteful number, since it uses less digits than its factorization.

11561778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173 (or 164 counting only the distinct ones).

The product of its digits is 11760, while the sum is 36.

The square root of 11561778 is about 3400.2614605351. The cubic root of 11561778 is about 226.1213356336.

The spelling of 11561778 in words is "eleven million, five hundred sixty-one thousand, seven hundred seventy-eight".