20516671673 has 4 divisors (see below), whose sum is σ = 21224143140. Its totient is φ = 19809200208.

The previous prime is 20516671649. The next prime is 20516671691. The reversal of 20516671673 is 37617661502.

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

It can be written as a sum of positive squares in 2 ways, for example, as 17126171689 + 3390499984 = 130867^2 + 58228^2 .

It is a cyclic number.

It is not a de Polignac number, because 20516671673 - 2²² = 20512477369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20516671633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 353735690 + ... + 353735747.

It is an arithmetic number, because the mean of its divisors is an integer number (5306035785).

Almost surely, 2^20516671673 is an apocalyptic number.

It is an amenable number.

20516671673 is a deficient number, since it is larger than the sum of its proper divisors (707471467).

20516671673 is an equidigital number, since it uses as much as digits as its factorization.

20516671673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 707471466.

The product of its (nonzero) digits is 317520, while the sum is 44.

The spelling of 20516671673 in words is "twenty billion, five hundred sixteen million, six hundred seventy-one thousand, six hundred seventy-three".