20013056643 has 4 divisors (see below), whose sum is σ = 26684075528. Its totient is φ = 13342037760.

The previous prime is 20013056641. The next prime is 20013056647. The reversal of 20013056643 is 34665031002.

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

It is not a de Polignac number, because 20013056643 - 2¹ = 20013056641 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20013056643.

It is not an unprimeable number, because it can be changed into a prime (20013056641) 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, 3335509438 + ... + 3335509443.

It is an arithmetic number, because the mean of its divisors is an integer number (6671018882).

Almost surely, 2^20013056643 is an apocalyptic number.

20013056643 is a deficient number, since it is larger than the sum of its proper divisors (6671018885).

20013056643 is an equidigital number, since it uses as much as digits as its factorization.

20013056643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6671018884.

The product of its (nonzero) digits is 12960, while the sum is 30.

Adding to 20013056643 its reverse (34665031002), we get a palindrome (54678087645).

The spelling of 20013056643 in words is "twenty billion, thirteen million, fifty-six thousand, six hundred forty-three".