20209779 has 12 divisors (see below), whose sum is σ = 29261232. Its totient is φ = 13441200.

The previous prime is 20209771. The next prime is 20209789. The reversal of 20209779 is 97790202.

It is not a de Polignac number, because 20209779 - 2³ = 20209771 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20209771) 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 11 ways as a sum of consecutive naturals, for example, 1714 + ... + 6584.

It is an arithmetic number, because the mean of its divisors is an integer number (2438436).

Almost surely, 2^20209779 is an apocalyptic number.

20209779 is a deficient number, since it is larger than the sum of its proper divisors (9051453).

20209779 is a wasteful number, since it uses less digits than its factorization.

20209779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5338 (or 5335 counting only the distinct ones).

The product of its (nonzero) digits is 15876, while the sum is 36.

The square root of 20209779 is about 4495.5287786867. The cubic root of 20209779 is about 272.3875090496.

The spelling of 20209779 in words is "twenty million, two hundred nine thousand, seven hundred seventy-nine".