166716056721 has 16 divisors (see below), whose sum is σ = 227042150400. Its totient is φ = 108767511888.

The previous prime is 166716056707. The next prime is 166716056729. The reversal of 166716056721 is 127650617661.

It is not a de Polignac number, because 166716056721 - 2⁷ = 166716056593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (166716056729) 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, 1356610 + ... + 1474388.

It is an arithmetic number, because the mean of its divisors is an integer number (14190134400).

Almost surely, 2^166716056721 is an apocalyptic number.

It is an amenable number.

166716056721 is a deficient number, since it is larger than the sum of its proper divisors (60326093679).

166716056721 is a wasteful number, since it uses less digits than its factorization.

166716056721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127868.

The product of its (nonzero) digits is 635040, while the sum is 48.

The spelling of 166716056721 in words is "one hundred sixty-six billion, seven hundred sixteen million, fifty-six thousand, seven hundred twenty-one".