20320643654643 has 4 divisors (see below), whose sum is σ = 27094191539528. Its totient is φ = 13547095769760.

The previous prime is 20320643654639. The next prime is 20320643654737. The reversal of 20320643654643 is 34645634602302.

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

It is not a de Polignac number, because 20320643654643 - 2² = 20320643654639 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20320643654592 and 20320643654601.

It is not an unprimeable number, because it can be changed into a prime (20320643654243) 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, 3386773942438 + ... + 3386773942443.

It is an arithmetic number, because the mean of its divisors is an integer number (6773547884882).

Almost surely, 2^{20320643654643} is an apocalyptic number.

20320643654643 is a deficient number, since it is larger than the sum of its proper divisors (6773547884885).

20320643654643 is an equidigital number, since it uses as much as digits as its factorization.

20320643654643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6773547884884.

The product of its (nonzero) digits is 7464960, while the sum is 48.

The spelling of 20320643654643 in words is "twenty trillion, three hundred twenty billion, six hundred forty-three million, six hundred fifty-four thousand, six hundred forty-three".