21122160165 has 12 divisors (see below), whose sum is σ = 36611744364. Its totient is φ = 11265152064.

The previous prime is 21122160149. The next prime is 21122160197. The reversal of 21122160165 is 56106122112.

21122160165 is a `hidden beast` number, since 21 + 12 + 21 + 601 + 6 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 16717714209 + 4404445956 = 129297^2 + 66366^2 .

It is not a de Polignac number, because 21122160165 - 2⁴ = 21122160149 is a prime.

It is a super-2 number, since 2×21122160165² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

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 11 ways as a sum of consecutive naturals, for example, 234690624 + ... + 234690713.

It is an arithmetic number, because the mean of its divisors is an integer number (3050978697).

Almost surely, 2^21122160165 is an apocalyptic number.

It is an amenable number.

21122160165 is a deficient number, since it is larger than the sum of its proper divisors (15489584199).

21122160165 is a wasteful number, since it uses less digits than its factorization.

21122160165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 469381348 (or 469381345 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

Adding to 21122160165 its reverse (56106122112), we get a palindrome (77228282277).

The spelling of 21122160165 in words is "twenty-one billion, one hundred twenty-two million, one hundred sixty thousand, one hundred sixty-five".