66515556565 has 16 divisors (see below), whose sum is σ = 84620321280. Its totient is φ = 50104128960.

The previous prime is 66515556521. The next prime is 66515556589. The reversal of 66515556565 is 56565551566.

It is not a de Polignac number, because 66515556565 - 2¹¹ = 66515554517 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5793355 + ... + 5804824.

It is an arithmetic number, because the mean of its divisors is an integer number (5288770080).

Almost surely, 2^66515556565 is an apocalyptic number.

It is an amenable number.

66515556565 is a deficient number, since it is larger than the sum of its proper divisors (18104764715).

66515556565 is a wasteful number, since it uses less digits than its factorization.

66515556565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11598252.

The product of its digits is 20250000, while the sum is 55.

The spelling of 66515556565 in words is "sixty-six billion, five hundred fifteen million, five hundred fifty-six thousand, five hundred sixty-five".