166665613009 has 9 divisors (see below), whose sum is σ = 193879649691. Its totient is φ = 142853790240.

The previous prime is 166665613003. The next prime is 166665613033. The reversal of 166665613009 is 900316566661.

The square root of 166665613009 is 408247.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 2056894609 + 164608718400 = 45353^2 + 405720^2 .

It is not a de Polignac number, because 166665613009 - 2⁹ = 166665612497 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is not an unprimeable number, because it can be changed into a prime (166665613003) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2828569 + ... + 2886889.

It is an arithmetic number, because the mean of its divisors is an integer number (21542183299).

Almost surely, 2^166665613009 is an apocalyptic number.

166665613009 is the 408247-th square number.

166665613009 is the 204124-th centered octagonal number.

It is an amenable number.

166665613009 is a deficient number, since it is larger than the sum of its proper divisors (27214036682).

166665613009 is an frugal number, since it uses more digits than its factorization.

166665613009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116656 (or 58328 counting only the distinct ones).

The product of its (nonzero) digits is 1049760, while the sum is 49.

Multiplying 166665613009 by its sum of digits (49), we get a square (8166615037441 = 2857729²).

166665613009 divided by its sum of digits (49) gives a square (3401339041 = 58321²).

The spelling of 166665613009 in words is "one hundred sixty-six billion, six hundred sixty-five million, six hundred thirteen thousand, nine".