6641620565 has 8 divisors (see below), whose sum is σ = 7977086520. Its totient is φ = 5308535232.

The previous prime is 6641620549. The next prime is 6641620597. The reversal of 6641620565 is 5650261466.

It can be written as a sum of positive squares in 4 ways, for example, as 995150116 + 5646470449 = 31546^2 + 75143^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6641620565 - 2⁴ = 6641620549 is a prime.

It is a super-2 number, since 2×6641620565² = 88222247458861838450, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 589010 + ... + 600179.

It is an arithmetic number, because the mean of its divisors is an integer number (997135815).

Almost surely, 2^6641620565 is an apocalyptic number.

It is an amenable number.

6641620565 is a deficient number, since it is larger than the sum of its proper divisors (1335465955).

6641620565 is a wasteful number, since it uses less digits than its factorization.

6641620565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1190311.

The product of its (nonzero) digits is 259200, while the sum is 41.

The square root of 6641620565 is about 81496.1383440958. The cubic root of 6641620565 is about 1879.7121715875.

The spelling of 6641620565 in words is "six billion, six hundred forty-one million, six hundred twenty thousand, five hundred sixty-five".