20664071845 has 8 divisors (see below), whose sum is σ = 24797907576. Its totient is φ = 16530576576.

The previous prime is 20664071839. The next prime is 20664071881. The reversal of 20664071845 is 54817046602.

It can be written as a sum of positive squares in 4 ways, for example, as 10040440804 + 10623631041 = 100202^2 + 103071^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20664071845 - 2³ = 20664071837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76219 + ... + 217111.

It is an arithmetic number, because the mean of its divisors is an integer number (3099738447).

Almost surely, 2^20664071845 is an apocalyptic number.

It is an amenable number.

20664071845 is a deficient number, since it is larger than the sum of its proper divisors (4133835731).

20664071845 is a wasteful number, since it uses less digits than its factorization.

20664071845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170231.

The product of its (nonzero) digits is 322560, while the sum is 43.

The spelling of 20664071845 in words is "twenty billion, six hundred sixty-four million, seventy-one thousand, eight hundred forty-five".