66840909690 has 64 divisors (see below), whose sum is σ = 164386454400. Its totient is φ = 17383618560.

The previous prime is 66840909679. The next prime is 66840909691. The reversal of 66840909690 is 9690904866.

It is a super-2 number, since 2×66840909690² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 66840909690.

It is not an unprimeable number, because it can be changed into a prime (66840909691) 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, 4539961 + ... + 4554659.

It is an arithmetic number, because the mean of its divisors is an integer number (2568538350).

Almost surely, 2^66840909690 is an apocalyptic number.

66840909690 is an abundant number, since it is smaller than the sum of its proper divisors (97545544710).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66840909690 is a wasteful number, since it uses less digits than its factorization.

66840909690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18447.

The product of its (nonzero) digits is 5038848, while the sum is 57.

The spelling of 66840909690 in words is "sixty-six billion, eight hundred forty million, nine hundred nine thousand, six hundred ninety".