1659549665 has 4 divisors (see below), whose sum is σ = 1991459604. Its totient is φ = 1327639728.

The previous prime is 1659549653. The next prime is 1659549677. The reversal of 1659549665 is 5669459561.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5669459561 = 181 ⋅31322981.

It is an interprime number because it is at equal distance from previous prime (1659549653) and next prime (1659549677).

It can be written as a sum of positive squares in 2 ways, for example, as 456292321 + 1203257344 = 21361^2 + 34688^2 .

It is a cyclic number.

It is not a de Polignac number, because 1659549665 - 2⁶ = 1659549601 is a prime.

It is a super-2 number, since 2×1659549665² = 5508210181203224450, which contains 22 as substring.

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 1659549665.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 165954962 + ... + 165954971.

It is an arithmetic number, because the mean of its divisors is an integer number (497864901).

Almost surely, 2^1659549665 is an apocalyptic number.

It is an amenable number.

1659549665 is a deficient number, since it is larger than the sum of its proper divisors (331909939).

1659549665 is an equidigital number, since it uses as much as digits as its factorization.

1659549665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 331909938.

The product of its digits is 8748000, while the sum is 56.

The square root of 1659549665 is about 40737.5706811292. The cubic root of 1659549665 is about 1183.9410659067.

The spelling of 1659549665 in words is "one billion, six hundred fifty-nine million, five hundred forty-nine thousand, six hundred sixty-five".