20009779 has 4 divisors (see below), whose sum is σ = 20387376. Its totient is φ = 19632184.

The previous prime is 20009761. The next prime is 20009813. The reversal of 20009779 is 97790002.

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 20009779 - 2⁷ = 20009651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20009719) 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, 188719 + ... + 188824.

It is an arithmetic number, because the mean of its divisors is an integer number (5096844).

Almost surely, 2^20009779 is an apocalyptic number.

20009779 is a deficient number, since it is larger than the sum of its proper divisors (377597).

20009779 is an equidigital number, since it uses as much as digits as its factorization.

20009779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 377596.

The product of its (nonzero) digits is 7938, while the sum is 34.

The square root of 20009779 is about 4473.2291468245. The cubic root of 20009779 is about 271.4859949341.

The spelling of 20009779 in words is "twenty million, nine thousand, seven hundred seventy-nine".