66561335635 has 16 divisors (see below), whose sum is σ = 80694070272. Its totient is φ = 52704086400.

The previous prime is 66561335573. The next prime is 66561335647. The reversal of 66561335635 is 53653316566.

It is not a de Polignac number, because 66561335635 - 2²¹ = 66559238483 is a prime.

It is a super-2 number, since 2×66561335635² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 142845 + ... + 391825.

It is an arithmetic number, because the mean of its divisors is an integer number (5043379392).

Almost surely, 2^66561335635 is an apocalyptic number.

66561335635 is a deficient number, since it is larger than the sum of its proper divisors (14132734637).

66561335635 is a wasteful number, since it uses less digits than its factorization.

66561335635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249534.

The product of its digits is 4374000, while the sum is 49.

The spelling of 66561335635 in words is "sixty-six billion, five hundred sixty-one million, three hundred thirty-five thousand, six hundred thirty-five".