20655664065 has 16 divisors (see below), whose sum is σ = 36721180800. Its totient is φ = 11016354096.

The previous prime is 20655664063. The next prime is 20655664069. The reversal of 20655664065 is 56046655602.

It is a happy number.

20655664065 is a `hidden beast` number, since 20 + 6 + 5 + 566 + 4 + 0 + 65 = 666.

It is not a de Polignac number, because 20655664065 - 2¹ = 20655664063 is a prime.

It is a super-2 number, since 2×20655664065² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 20655664065.

It is not an unprimeable number, because it can be changed into a prime (20655664063) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 76502325 + ... + 76502594.

It is an arithmetic number, because the mean of its divisors is an integer number (2295073800).

Almost surely, 2^20655664065 is an apocalyptic number.

It is an amenable number.

20655664065 is a deficient number, since it is larger than the sum of its proper divisors (16065516735).

20655664065 is a wasteful number, since it uses less digits than its factorization.

20655664065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153004933 (or 153004927 counting only the distinct ones).

The product of its (nonzero) digits is 1296000, while the sum is 45.

The spelling of 20655664065 in words is "twenty billion, six hundred fifty-five million, six hundred sixty-four thousand, sixty-five".