166516121889 has 24 divisors (see below), whose sum is σ = 259276017000. Its totient is φ = 102372187392.

The previous prime is 166516121843. The next prime is 166516121939. The reversal of 166516121889 is 988121615661.

166516121889 is a `hidden beast` number, since 1 + 6 + 6 + 5 + 1 + 612 + 18 + 8 + 9 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 37054325025 + 129461796864 = 192495^2 + 359808^2 .

It is not a de Polignac number, because 166516121889 - 2¹⁶ = 166516056353 is a prime.

It is not an unprimeable number, because it can be changed into a prime (166516121819) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 568014 + ... + 809735.

It is an arithmetic number, because the mean of its divisors is an integer number (10803167375).

Almost surely, 2^166516121889 is an apocalyptic number.

It is an amenable number.

166516121889 is a deficient number, since it is larger than the sum of its proper divisors (92759895111).

166516121889 is a wasteful number, since it uses less digits than its factorization.

166516121889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1378801 (or 1378798 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 54.

The spelling of 166516121889 in words is "one hundred sixty-six billion, five hundred sixteen million, one hundred twenty-one thousand, eight hundred eighty-nine".