1641616565 has 4 divisors (see below), whose sum is σ = 1969939884. Its totient is φ = 1313293248.

The previous prime is 1641616553. The next prime is 1641616573. The reversal of 1641616565 is 5656161461.

1641616565 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5656161461 = 5783 ⋅978067.

It can be written as a sum of positive squares in 2 ways, for example, as 1231027396 + 410589169 = 35086^2 + 20263^2 .

It is a cyclic number.

It is not a de Polignac number, because 1641616565 - 2⁸ = 1641616309 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

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, 164161652 + ... + 164161661.

It is an arithmetic number, because the mean of its divisors is an integer number (492484971).

Almost surely, 2^1641616565 is an apocalyptic number.

It is an amenable number.

1641616565 is a deficient number, since it is larger than the sum of its proper divisors (328323319).

1641616565 is an equidigital number, since it uses as much as digits as its factorization.

1641616565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328323318.

The product of its digits is 129600, while the sum is 41.

The square root of 1641616565 is about 40516.8676602721. The cubic root of 1641616565 is about 1179.6610548574.

The spelling of 1641616565 in words is "one billion, six hundred forty-one million, six hundred sixteen thousand, five hundred sixty-five".