1665155549 has 4 divisors (see below), whose sum is σ = 1672491264. Its totient is φ = 1657819836.

The previous prime is 1665155543. The next prime is 1665155551. The reversal of 1665155549 is 9455515661.

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.

It is a cyclic number.

It is not a de Polignac number, because 1665155549 - 2⁴ = 1665155533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665155543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3667517 + ... + 3667970.

It is an arithmetic number, because the mean of its divisors is an integer number (418122816).

Almost surely, 2^1665155549 is an apocalyptic number.

It is an amenable number.

1665155549 is a deficient number, since it is larger than the sum of its proper divisors (7335715).

1665155549 is an equidigital number, since it uses as much as digits as its factorization.

1665155549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7335714.

The product of its digits is 810000, while the sum is 47.

The square root of 1665155549 is about 40806.3175133459. The cubic root of 1665155549 is about 1185.2726675269.

The spelling of 1665155549 in words is "one billion, six hundred sixty-five million, one hundred fifty-five thousand, five hundred forty-nine".