1665345181 has 2 divisors, whose sum is σ = 1665345182. Its totient is φ = 1665345180.

The previous prime is 1665345163. The next prime is 1665345197. The reversal of 1665345181 is 1815435661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1657222681 + 8122500 = 40709^2 + 2850^2 .

It is a cyclic number.

It is not a de Polignac number, because 1665345181 - 2⁷ = 1665345053 is a prime.

It is a super-2 number, since 2×1665345181² = 5546749143759845522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1665345281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832672590 + 832672591.

It is an arithmetic number, because the mean of its divisors is an integer number (832672591).

Almost surely, 2^1665345181 is an apocalyptic number.

It is an amenable number.

1665345181 is a deficient number, since it is larger than the sum of its proper divisors (1).

1665345181 is an equidigital number, since it uses as much as digits as its factorization.

1665345181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 86400, while the sum is 40.

The square root of 1665345181 is about 40808.6410089824. The cubic root of 1665345181 is about 1185.3176597390.

The spelling of 1665345181 in words is "one billion, six hundred sixty-five million, three hundred forty-five thousand, one hundred eighty-one".