166665454821 has 32 divisors (see below), whose sum is σ = 255461040000. Its totient is φ = 107264191104.

The previous prime is 166665454807. The next prime is 166665454843. The reversal of 166665454821 is 128454566661.

It is not a de Polignac number, because 166665454821 - 2¹⁰ = 166665453797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166665454871) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10886230 + ... + 10901528.

It is an arithmetic number, because the mean of its divisors is an integer number (7983157500).

Almost surely, 2^166665454821 is an apocalyptic number.

It is an amenable number.

166665454821 is a deficient number, since it is larger than the sum of its proper divisors (88795585179).

166665454821 is a wasteful number, since it uses less digits than its factorization.

166665454821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29250 (or 29244 counting only the distinct ones).

The product of its digits is 8294400, while the sum is 54.

The spelling of 166665454821 in words is "one hundred sixty-six billion, six hundred sixty-five million, four hundred fifty-four thousand, eight hundred twenty-one".