166540161145521 has 8 divisors (see below), whose sum is σ = 222221643239584. Its totient is φ = 110942726574240.

The previous prime is 166540161145517. The next prime is 166540161145543. The reversal of 166540161145521 is 125541161045661.

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

It is not a de Polignac number, because 166540161145521 - 2² = 166540161145517 is a prime.

It is a super-2 number, since 2×166540161145521² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (166540161145571) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21011876071 + ... + 21011883996.

It is an arithmetic number, because the mean of its divisors is an integer number (27777705404948).

Almost surely, 2^{166540161145521} is an apocalyptic number.

It is an amenable number.

166540161145521 is a deficient number, since it is larger than the sum of its proper divisors (55681482094063).

166540161145521 is a wasteful number, since it uses less digits than its factorization.

166540161145521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42023761391.

The product of its (nonzero) digits is 864000, while the sum is 48.

The spelling of 166540161145521 in words is "one hundred sixty-six trillion, five hundred forty billion, one hundred sixty-one million, one hundred forty-five thousand, five hundred twenty-one".