666191161 has 8 divisors (see below), whose sum is σ = 695265480. Its totient is φ = 637523712.

The previous prime is 666191101. The next prime is 666191191. The reversal of 666191161 is 161191666.

It can be written as a sum of positive squares in 4 ways, for example, as 35176761 + 631014400 = 5931^2 + 25120^2 .

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 666191161 - 2¹³ = 666182969 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 666191161.

It is not an unprimeable number, because it can be changed into a prime (666191101) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 98370 + ... + 104923.

It is an arithmetic number, because the mean of its divisors is an integer number (86908185).

Almost surely, 2^666191161 is an apocalyptic number.

It is an amenable number.

666191161 is a deficient number, since it is larger than the sum of its proper divisors (29074319).

666191161 is a wasteful number, since it uses less digits than its factorization.

666191161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203435.

The product of its digits is 11664, while the sum is 37.

The square root of 666191161 is about 25810.6792045463. The cubic root of 666191161 is about 873.3727191057.

The spelling of 666191161 in words is "six hundred sixty-six million, one hundred ninety-one thousand, one hundred sixty-one".