65661720561075 has 12 divisors (see below), whose sum is σ = 108560711327768. Its totient is φ = 35019584299200.

The previous prime is 65661720561043. The next prime is 65661720561097. The reversal of 65661720561075 is 57016502716656.

It is not a de Polignac number, because 65661720561075 - 2⁵ = 65661720561043 is a prime.

It is a super-2 number, since 2×65661720561075² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 437744803666 + ... + 437744803815.

Almost surely, 2^{65661720561075} is an apocalyptic number.

65661720561075 is a deficient number, since it is larger than the sum of its proper divisors (42898990766693).

65661720561075 is a wasteful number, since it uses less digits than its factorization.

65661720561075 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 875489607494 (or 875489607489 counting only the distinct ones).

The product of its (nonzero) digits is 15876000, while the sum is 57.

The spelling of 65661720561075 in words is "sixty-five trillion, six hundred sixty-one billion, seven hundred twenty million, five hundred sixty-one thousand, seventy-five".