66861756069 has 32 divisors (see below), whose sum is σ = 90202844160. Its totient is φ = 44051868672.

The previous prime is 66861756061. The next prime is 66861756119. The reversal of 66861756069 is 96065716866.

It is not a de Polignac number, because 66861756069 - 2³ = 66861756061 is a prime.

It is a super-2 number, since 2×66861756069² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66861756061) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 77475532 + ... + 77476394.

It is an arithmetic number, because the mean of its divisors is an integer number (2818838880).

Almost surely, 2^66861756069 is an apocalyptic number.

It is an amenable number.

66861756069 is a deficient number, since it is larger than the sum of its proper divisors (23341088091).

66861756069 is a wasteful number, since it uses less digits than its factorization.

66861756069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1789.

The product of its (nonzero) digits is 19595520, while the sum is 60.

The spelling of 66861756069 in words is "sixty-six billion, eight hundred sixty-one million, seven hundred fifty-six thousand, sixty-nine".