165012000000021 has 12 divisors (see below), whose sum is σ = 238351012312972. Its totient is φ = 110007840470976.

The previous prime is 165012000000013. The next prime is 165012000000079. The reversal of 165012000000021 is 120000000210561.

165012000000021 is a `hidden beast` number, since 1 + 650 + 12 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 2 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 127698362136900 + 37313637863121 = 11300370^2 + 6108489^2 .

It is not a de Polignac number, because 165012000000021 - 2³ = 165012000000013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 165011999999940 and 165012000000003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165012000000121) 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, 6563746 + ... + 19315971.

Almost surely, 2^{165012000000021} is an apocalyptic number.

It is an amenable number.

165012000000021 is a deficient number, since it is larger than the sum of its proper divisors (73339012312951).

165012000000021 is a wasteful number, since it uses less digits than its factorization.

165012000000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26588180 (or 26588177 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

Adding to 165012000000021 its reverse (120000000210561), we get a palindrome (285012000210582).

The spelling of 165012000000021 in words is "one hundred sixty-five trillion, twelve billion, twenty-one", and thus it is an aban number.