20806455797 has 4 divisors (see below), whose sum is σ = 21523919820. Its totient is φ = 20088991776.

The previous prime is 20806455781. The next prime is 20806455821. The reversal of 20806455797 is 79755460802.

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 10049862001 + 10756593796 = 100249^2 + 103714^2 .

It is a cyclic number.

It is not a de Polignac number, because 20806455797 - 2⁴ = 20806455781 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20806455767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 358731968 + ... + 358732025.

It is an arithmetic number, because the mean of its divisors is an integer number (5380979955).

Almost surely, 2^20806455797 is an apocalyptic number.

It is an amenable number.

20806455797 is a deficient number, since it is larger than the sum of its proper divisors (717464023).

20806455797 is an equidigital number, since it uses as much as digits as its factorization.

20806455797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 717464022.

The product of its (nonzero) digits is 4233600, while the sum is 53.

The spelling of 20806455797 in words is "twenty billion, eight hundred six million, four hundred fifty-five thousand, seven hundred ninety-seven".