66806186940 has 252 divisors, whose sum is σ = 216246456216. Its totient is φ = 17328318336.

The previous prime is 66806186933. The next prime is 66806186947. The reversal of 66806186940 is 4968160866.

It is an interprime number because it is at equal distance from previous prime (66806186933) and next prime (66806186947).

It is a super-2 number, since 2×66806186940² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66806186947) by changing a digit.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 19958347 + ... + 19961693.

It is an arithmetic number, because the mean of its divisors is an integer number (858120858).

Almost surely, 2^66806186940 is an apocalyptic number.

66806186940 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 66806186940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108123228108).

66806186940 is an abundant number, since it is smaller than the sum of its proper divisors (149440269276).

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

66806186940 is a wasteful number, since it uses less digits than its factorization.

66806186940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3448 (or 3394 counting only the distinct ones).

The product of its (nonzero) digits is 2985984, while the sum is 54.

The spelling of 66806186940 in words is "sixty-six billion, eight hundred six million, one hundred eighty-six thousand, nine hundred forty".