20656720006173 has 12 divisors (see below), whose sum is σ = 29887130857948. Its totient is φ = 13748232945600.

The previous prime is 20656720006171. The next prime is 20656720006177. The reversal of 20656720006173 is 37160002765602.

20656720006173 is a `hidden beast` number, since 2 + 0 + 6 + 5 + 6 + 7 + 20 + 0 + 0 + 617 + 3 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 13321061938809 + 7335658067364 = 3649803^2 + 2708442^2 .

It is not a de Polignac number, because 20656720006173 - 2¹ = 20656720006171 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20656720006171) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1909471390 + ... + 1909482207.

Almost surely, 2^{20656720006173} is an apocalyptic number.

It is an amenable number.

20656720006173 is a deficient number, since it is larger than the sum of its proper divisors (9230410851775).

20656720006173 is a wasteful number, since it uses less digits than its factorization.

20656720006173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3818954204 (or 3818954201 counting only the distinct ones).

The product of its (nonzero) digits is 635040, while the sum is 45.

The spelling of 20656720006173 in words is "twenty trillion, six hundred fifty-six billion, seven hundred twenty million, six thousand, one hundred seventy-three".