20616265665 has 16 divisors (see below), whose sum is σ = 36651139200. Its totient is φ = 10995341616.

The previous prime is 20616265639. The next prime is 20616265679. The reversal of 20616265665 is 56656261602.

It is a happy number.

20616265665 is a `hidden beast` number, since 2 + 0 + 61 + 6 + 26 + 566 + 5 = 666.

It is not a de Polignac number, because 20616265665 - 2⁶ = 20616265601 is a prime.

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

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20616265665.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 76356405 + ... + 76356674.

It is an arithmetic number, because the mean of its divisors is an integer number (2290696200).

Almost surely, 2^20616265665 is an apocalyptic number.

It is an amenable number.

20616265665 is a deficient number, since it is larger than the sum of its proper divisors (16034873535).

20616265665 is a wasteful number, since it uses less digits than its factorization.

20616265665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152713093 (or 152713087 counting only the distinct ones).

The product of its (nonzero) digits is 777600, while the sum is 45.

The spelling of 20616265665 in words is "twenty billion, six hundred sixteen million, two hundred sixty-five thousand, six hundred sixty-five".