20806553817 has 48 divisors (see below), whose sum is σ = 35585297280. Its totient is φ = 11462169600.

The previous prime is 20806553813. The next prime is 20806553851. The reversal of 20806553817 is 71835560802.

20806553817 is a `hidden beast` number, since 2 + 0 + 80 + 6 + 553 + 8 + 17 = 666.

It is not a de Polignac number, because 20806553817 - 2² = 20806553813 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20806553813) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1254217 + ... + 1270697.

It is an arithmetic number, because the mean of its divisors is an integer number (741360360).

Almost surely, 2^20806553817 is an apocalyptic number.

It is an amenable number.

20806553817 is a deficient number, since it is larger than the sum of its proper divisors (14778743463).

20806553817 is a wasteful number, since it uses less digits than its factorization.

20806553817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17214 (or 17211 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The spelling of 20806553817 in words is "twenty billion, eight hundred six million, five hundred fifty-three thousand, eight hundred seventeen".