66649893660 has 768 divisors, whose sum is σ = 267853824000. Its totient is φ = 13392138240.

The previous prime is 66649893631. The next prime is 66649893671. The reversal of 66649893660 is 6639894666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 96453915 + ... + 96454605.

It is an arithmetic number, because the mean of its divisors is an integer number (348768000).

Almost surely, 2^66649893660 is an apocalyptic number.

66649893660 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66649893660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133926912000).

66649893660 is an abundant number, since it is smaller than the sum of its proper divisors (201203930340).

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

66649893660 is a wasteful number, since it uses less digits than its factorization.

66649893660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 831 (or 823 counting only the distinct ones).

The product of its (nonzero) digits is 60466176, while the sum is 63.

The spelling of 66649893660 in words is "sixty-six billion, six hundred forty-nine million, eight hundred ninety-three thousand, six hundred sixty".