66365475840 has 264 divisors, whose sum is σ = 243484263360. Its totient is φ = 16656236544.

The previous prime is 66365475821. The next prime is 66365475859. The reversal of 66365475840 is 4857456366.

66365475840 is a `hidden beast` number, since 6 + 6 + 3 + 6 + 54 + 7 + 584 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (66365475821) and next prime (66365475859).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 741001 + ... + 825719.

Almost surely, 2^66365475840 is an apocalyptic number.

66365475840 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 66365475840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121742131680).

66365475840 is an abundant number, since it is smaller than the sum of its proper divisors (177118787520).

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

66365475840 is a wasteful number, since it uses less digits than its factorization.

66365475840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84767 (or 84746 counting only the distinct ones).

The product of its (nonzero) digits is 14515200, while the sum is 54.

The spelling of 66365475840 in words is "sixty-six billion, three hundred sixty-five million, four hundred seventy-five thousand, eight hundred forty".