20566779 has 4 divisors (see below), whose sum is σ = 27422376. Its totient is φ = 13711184.

The previous prime is 20566769. The next prime is 20566811. The reversal of 20566779 is 97766502.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20566779 - 2⁹ = 20566267 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20566779.

It is not an unprimeable number, because it can be changed into a prime (20566729) 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, 3427794 + ... + 3427799.

It is an arithmetic number, because the mean of its divisors is an integer number (6855594).

Almost surely, 2^20566779 is an apocalyptic number.

20566779 is a deficient number, since it is larger than the sum of its proper divisors (6855597).

20566779 is an equidigital number, since it uses as much as digits as its factorization.

20566779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6855596.

The product of its (nonzero) digits is 158760, while the sum is 42.

The square root of 20566779 is about 4535.0610800738. The cubic root of 20566779 is about 273.9820392440.

The spelling of 20566779 in words is "twenty million, five hundred sixty-six thousand, seven hundred seventy-nine".