20646438611 has 4 divisors (see below), whose sum is σ = 21358384800. Its totient is φ = 19934492424.

The previous prime is 20646438563. The next prime is 20646438643. The reversal of 20646438611 is 11683464602.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11683464602 = 2 ⋅5841732301.

It is a cyclic number.

It is not a de Polignac number, because 20646438611 - 2²² = 20642244307 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20646438011) 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, 355973051 + ... + 355973108.

It is an arithmetic number, because the mean of its divisors is an integer number (5339596200).

Almost surely, 2^20646438611 is an apocalyptic number.

20646438611 is a deficient number, since it is larger than the sum of its proper divisors (711946189).

20646438611 is an equidigital number, since it uses as much as digits as its factorization.

20646438611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 711946188.

The product of its (nonzero) digits is 165888, while the sum is 41.

The spelling of 20646438611 in words is "twenty billion, six hundred forty-six million, four hundred thirty-eight thousand, six hundred eleven".