20779220845 has 4 divisors (see below), whose sum is σ = 24935065020. Its totient is φ = 16623376672.

The previous prime is 20779220837. The next prime is 20779220849. The reversal of 20779220845 is 54802297702.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8458664841 + 12320556004 = 91971^2 + 110998^2 .

It is a cyclic number.

It is not a de Polignac number, because 20779220845 - 2³ = 20779220837 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20779220795 and 20779220804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20779220849) 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, 2077922080 + ... + 2077922089.

It is an arithmetic number, because the mean of its divisors is an integer number (6233766255).

Almost surely, 2^20779220845 is an apocalyptic number.

It is an amenable number.

20779220845 is a deficient number, since it is larger than the sum of its proper divisors (4155844175).

20779220845 is an equidigital number, since it uses as much as digits as its factorization.

20779220845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4155844174.

The product of its (nonzero) digits is 564480, while the sum is 46.

The spelling of 20779220845 in words is "twenty billion, seven hundred seventy-nine million, two hundred twenty thousand, eight hundred forty-five".