5561666779 has 4 divisors (see below), whose sum is σ = 5563406376. Its totient is φ = 5559927184.

The previous prime is 5561666713. The next prime is 5561666783. The reversal of 5561666779 is 9776661655.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-5561666779 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5561669779) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 864994 + ... + 871399.

It is an arithmetic number, because the mean of its divisors is an integer number (1390851594).

Almost surely, 2^5561666779 is an apocalyptic number.

5561666779 is a deficient number, since it is larger than the sum of its proper divisors (1739597).

5561666779 is a wasteful number, since it uses less digits than its factorization.

5561666779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1739596.

The product of its digits is 14288400, while the sum is 58.

The square root of 5561666779 is about 74576.5833154081. The cubic root of 5561666779 is about 1771.7467917229.

The spelling of 5561666779 in words is "five billion, five hundred sixty-one million, six hundred sixty-six thousand, seven hundred seventy-nine".