66985574400 has 540 divisors, whose sum is σ = 249206666072. Its totient is φ = 17836277760.

The previous prime is 66985574399. The next prime is 66985574401. The reversal of 66985574400 is 447558966.

66985574400 is a `hidden beast` number, since 6 + 69 + 8 + 5 + 574 + 4 + 0 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (66985574399) and next prime (66985574401).

It is a tau number, because it is divible by the number of its divisors (540).

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

It is not an unprimeable number, because it can be changed into a prime (66985574401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 99532464 + ... + 99533136.

Almost surely, 2^66985574400 is an apocalyptic number.

66985574400 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 66985574400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124603333036).

66985574400 is an abundant number, since it is smaller than the sum of its proper divisors (182221091672).

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

66985574400 is an frugal number, since it uses more digits than its factorization.

66985574400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 726 (or 683 counting only the distinct ones).

The product of its (nonzero) digits is 7257600, while the sum is 54.

The spelling of 66985574400 in words is "sixty-six billion, nine hundred eighty-five million, five hundred seventy-four thousand, four hundred".