66615755751666 has 48 divisors (see below), whose sum is σ = 157571114302368. Its totient is φ = 20171760393600.

The previous prime is 66615755751661. The next prime is 66615755751667.

66615755751666 is nontrivially palindromic in base 10.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 66615755751594 and 66615755751603.

It is not an unprimeable number, because it can be changed into a prime (66615755751661) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 123331996 + ... + 123870951.

It is an arithmetic number, because the mean of its divisors is an integer number (3282731547966).

Almost surely, 2^{66615755751666} is an apocalyptic number.

66615755751666 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

66615755751666 is an abundant number, since it is smaller than the sum of its proper divisors (90955358550702).

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

66615755751666 is a wasteful number, since it uses less digits than its factorization.

66615755751666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247204327 (or 247204324 counting only the distinct ones).

The product of its digits is 1428840000, while the sum is 72.

The spelling of 66615755751666 in words is "sixty-six trillion, six hundred fifteen billion, seven hundred fifty-five million, seven hundred fifty-one thousand, six hundred sixty-six".