166661500001571 has 12 divisors (see below), whose sum is σ = 243633678718248. Its totient is φ = 109769020080864.

The previous prime is 166661500001551. The next prime is 166661500001681. The reversal of 166661500001571 is 175100005166661.

It is not a de Polignac number, because 166661500001571 - 2¹³ = 166661499993379 is a prime.

It is not an unprimeable number, because it can be changed into a prime (166661500001551) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 111553881450 + ... + 111553882943.

It is an arithmetic number, because the mean of its divisors is an integer number (20302806559854).

Almost surely, 2^{166661500001571} is an apocalyptic number.

166661500001571 is a deficient number, since it is larger than the sum of its proper divisors (76972178716677).

166661500001571 is a wasteful number, since it uses less digits than its factorization.

166661500001571 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223107764482 (or 223107764479 counting only the distinct ones).

The product of its (nonzero) digits is 226800, while the sum is 45.

The spelling of 166661500001571 in words is "one hundred sixty-six trillion, six hundred sixty-one billion, five hundred million, one thousand, five hundred seventy-one".