166500180021 has 16 divisors (see below), whose sum is σ = 253720552064. Its totient is φ = 95140713024.

The previous prime is 166500180001. The next prime is 166500180031. The reversal of 166500180021 is 120081005661.

It is not a de Polignac number, because 166500180021 - 2¹⁰ = 166500178997 is a prime.

It is a super-3 number, since 3×166500180021³ (a number of 35 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166500180001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1297275 + ... + 1419831.

It is an arithmetic number, because the mean of its divisors is an integer number (15857534504).

Almost surely, 2^166500180021 is an apocalyptic number.

It is an amenable number.

166500180021 is a deficient number, since it is larger than the sum of its proper divisors (87220372043).

166500180021 is a wasteful number, since it uses less digits than its factorization.

166500180021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187260.

The product of its (nonzero) digits is 2880, while the sum is 30.

Adding to 166500180021 its reverse (120081005661), we get a palindrome (286581185682).

The spelling of 166500180021 in words is "one hundred sixty-six billion, five hundred million, one hundred eighty thousand, twenty-one".