1661166011 has 4 divisors (see below), whose sum is σ = 1661487024. Its totient is φ = 1660845000.

The previous prime is 1661165977. The next prime is 1661166019. The reversal of 1661166011 is 1106611661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1106611661 = 19 ⋅58242719.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1661166011 is a prime.

It is a super-2 number, since 2×1661166011² = 5518945032203304242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661166019) 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, 152615 + ... + 163136.

It is an arithmetic number, because the mean of its divisors is an integer number (415371756).

Almost surely, 2^1661166011 is an apocalyptic number.

1661166011 is a deficient number, since it is larger than the sum of its proper divisors (321013).

1661166011 is an equidigital number, since it uses as much as digits as its factorization.

1661166011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321012.

The product of its (nonzero) digits is 1296, while the sum is 29.

The square root of 1661166011 is about 40757.4043702491. The cubic root of 1661166011 is about 1184.3253142167.

Adding to 1661166011 its reverse (1106611661), we get a palindrome (2767777672).

The spelling of 1661166011 in words is "one billion, six hundred sixty-one million, one hundred sixty-six thousand, eleven".