66418563743640 has 640 divisors, whose sum is σ = 232438185365760. Its totient is φ = 16997640016896.

The previous prime is 66418563743551. The next prime is 66418563743681. The reversal of 66418563743640 is 4634736581466.

66418563743640 is a `hidden beast` number, since 6 + 6 + 4 + 1 + 8 + 563 + 7 + 4 + 3 + 64 + 0 = 666.

It is a super-2 number, since 2×66418563743640² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 3705763719 + ... + 3705781641.

It is an arithmetic number, because the mean of its divisors is an integer number (363184664634).

Almost surely, 2^{66418563743640} is an apocalyptic number.

66418563743640 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 66418563743640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116219092682880).

66418563743640 is an abundant number, since it is smaller than the sum of its proper divisors (166019621622120).

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

66418563743640 is a wasteful number, since it uses less digits than its factorization.

66418563743640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18453 (or 18440 counting only the distinct ones).

The product of its (nonzero) digits is 209018880, while the sum is 63.

The spelling of 66418563743640 in words is "sixty-six trillion, four hundred eighteen billion, five hundred sixty-three million, seven hundred forty-three thousand, six hundred forty".