1666061161 has 4 divisors (see below), whose sum is σ = 1666142800. Its totient is φ = 1665979524.

The previous prime is 1666061147. The next prime is 1666061171. The reversal of 1666061161 is 1611606661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1666061161 - 2¹¹ = 1666059113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666061171) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19870 + ... + 61048.

It is an arithmetic number, because the mean of its divisors is an integer number (416535700).

Almost surely, 2^1666061161 is an apocalyptic number.

It is an amenable number.

1666061161 is a deficient number, since it is larger than the sum of its proper divisors (81639).

1666061161 is an equidigital number, since it uses as much as digits as its factorization.

1666061161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81638.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 1666061161 is about 40817.4124731101. The cubic root of 1666061161 is about 1185.4875028352.

The spelling of 1666061161 in words is "one billion, six hundred sixty-six million, sixty-one thousand, one hundred sixty-one".