66840787680 has 192 divisors, whose sum is σ = 225757808640. Its totient is φ = 16563216384.

The previous prime is 66840787679. The next prime is 66840787681. The reversal of 66840787680 is 8678704866.

It is an interprime number because it is at equal distance from previous prime (66840787679) and next prime (66840787681).

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66840787681) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 592797 + ... + 696483.

It is an arithmetic number, because the mean of its divisors is an integer number (1175821920).

Almost surely, 2^66840787680 is an apocalyptic number.

66840787680 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 66840787680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112878904320).

66840787680 is an abundant number, since it is smaller than the sum of its proper divisors (158917020960).

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

66840787680 is a wasteful number, since it uses less digits than its factorization.

66840787680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103801 (or 103793 counting only the distinct ones).

The product of its (nonzero) digits is 21676032, while the sum is 60.

The spelling of 66840787680 in words is "sixty-six billion, eight hundred forty million, seven hundred eighty-seven thousand, six hundred eighty".