66231554400 has 864 divisors, whose sum is σ = 269199770112. Its totient is φ = 15165849600.

The previous prime is 66231554399. The next prime is 66231554437. The reversal of 66231554400 is 445513266.

66231554400 is a `hidden beast` number, since 6 + 62 + 3 + 1 + 554 + 40 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 187624624 + ... + 187624976.

It is an arithmetic number, because the mean of its divisors is an integer number (311573808).

Almost surely, 2^66231554400 is an apocalyptic number.

66231554400 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 66231554400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134599885056).

66231554400 is an abundant number, since it is smaller than the sum of its proper divisors (202968215712).

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

66231554400 is a wasteful number, since it uses less digits than its factorization.

66231554400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 516 (or 500 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The spelling of 66231554400 in words is "sixty-six billion, two hundred thirty-one million, five hundred fifty-four thousand, four hundred".