11778561 has 16 divisors (see below), whose sum is σ = 17781120. Its totient is φ = 7703280.

The previous prime is 11778539. The next prime is 11778563. The reversal of 11778561 is 16587711.

It is a happy number.

It is not a de Polignac number, because 11778561 - 2⁹ = 11778049 is a prime.

It is not an unprimeable number, because it can be changed into a prime (11778563) 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 15 ways as a sum of consecutive naturals, for example, 2685 + ... + 5546.

It is an arithmetic number, because the mean of its divisors is an integer number (1111320).

Almost surely, 2^11778561 is an apocalyptic number.

It is an amenable number.

11778561 is a deficient number, since it is larger than the sum of its proper divisors (6002559).

11778561 is an equidigital number, since it uses as much as digits as its factorization.

11778561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8293 (or 8287 counting only the distinct ones).

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

The square root of 11778561 is about 3431.9908216660. The cubic root of 11778561 is about 227.5258498180.

The spelling of 11778561 in words is "eleven million, seven hundred seventy-eight thousand, five hundred sixty-one".