166511275621 has 8 divisors (see below), whose sum is σ = 170399223104. Its totient is φ = 162624036960.

The previous prime is 166511275613. The next prime is 166511275643. The reversal of 166511275621 is 126572115661.

It is a happy number.

166511275621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 166511275621 - 2³ = 166511275613 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166511276621) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 313801 + ... + 656881.

It is an arithmetic number, because the mean of its divisors is an integer number (21299902888).

Almost surely, 2^166511275621 is an apocalyptic number.

It is an amenable number.

166511275621 is a deficient number, since it is larger than the sum of its proper divisors (3887947483).

166511275621 is a wasteful number, since it uses less digits than its factorization.

166511275621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 354411.

The product of its digits is 151200, while the sum is 43.

The spelling of 166511275621 in words is "one hundred sixty-six billion, five hundred eleven million, two hundred seventy-five thousand, six hundred twenty-one".