20904723841 has 4 divisors (see below), whose sum is σ = 20972817712. Its totient is φ = 20836629972.

The previous prime is 20904723839. The next prime is 20904723911. The reversal of 20904723841 is 14832740902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20904723841 - 2¹ = 20904723839 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20904723794 and 20904723803.

It is not an unprimeable number, because it can be changed into a prime (20904720841) 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, 34046475 + ... + 34047088.

It is an arithmetic number, because the mean of its divisors is an integer number (5243204428).

Almost surely, 2^20904723841 is an apocalyptic number.

It is an amenable number.

20904723841 is a deficient number, since it is larger than the sum of its proper divisors (68093871).

20904723841 is an equidigital number, since it uses as much as digits as its factorization.

20904723841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68093870.

The product of its (nonzero) digits is 96768, while the sum is 40.

The spelling of 20904723841 in words is "twenty billion, nine hundred four million, seven hundred twenty-three thousand, eight hundred forty-one".