20646888309 has 8 divisors (see below), whose sum is σ = 30587982720. Its totient is φ = 13764592188.

The previous prime is 20646888287. The next prime is 20646888313. The reversal of 20646888309 is 90388864602.

It is not a de Polignac number, because 20646888309 - 2⁹ = 20646887797 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20646888349) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 382349757 + ... + 382349810.

It is an arithmetic number, because the mean of its divisors is an integer number (3823497840).

Almost surely, 2^20646888309 is an apocalyptic number.

It is an amenable number.

20646888309 is a deficient number, since it is larger than the sum of its proper divisors (9941094411).

20646888309 is an equidigital number, since it uses as much as digits as its factorization.

20646888309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 764699576 (or 764699570 counting only the distinct ones).

The product of its (nonzero) digits is 3981312, while the sum is 54.

The spelling of 20646888309 in words is "twenty billion, six hundred forty-six million, eight hundred eighty-eight thousand, three hundred nine".