20661182165 has 8 divisors (see below), whose sum is σ = 26700604728. Its totient is φ = 15257488320.

The previous prime is 20661182159. The next prime is 20661182209. The reversal of 20661182165 is 56128116602.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1076299249 + 19584882916 = 32807^2 + 139946^2 .

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

It is not a de Polignac number, because 20661182165 - 2¹⁰ = 20661181141 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, 158932106 + ... + 158932235.

It is an arithmetic number, because the mean of its divisors is an integer number (3337575591).

Almost surely, 2^20661182165 is an apocalyptic number.

It is an amenable number.

20661182165 is a deficient number, since it is larger than the sum of its proper divisors (6039422563).

20661182165 is a wasteful number, since it uses less digits than its factorization.

20661182165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317864359.

The product of its (nonzero) digits is 34560, while the sum is 38.

Adding to 20661182165 its reverse (56128116602), we get a palindrome (76789298767).

The spelling of 20661182165 in words is "twenty billion, six hundred sixty-one million, one hundred eighty-two thousand, one hundred sixty-five".