66421534500 has 144 divisors (see below), whose sum is σ = 213492110832. Its totient is φ = 17378150400.

The previous prime is 66421534493. The next prime is 66421534519. The reversal of 66421534500 is 543512466.

66421534500 is a `hidden beast` number, since 6 + 642 + 1 + 5 + 3 + 4 + 5 + 0 + 0 = 666.

66421534500 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 4333852224 + 62087682276 = 65832^2 + 249174^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 99252 + ... + 377748.

It is an arithmetic number, because the mean of its divisors is an integer number (1482584103).

Almost surely, 2^66421534500 is an apocalyptic number.

66421534500 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 66421534500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106746055416).

66421534500 is an abundant number, since it is smaller than the sum of its proper divisors (147070576332).

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

66421534500 is a wasteful number, since it uses less digits than its factorization.

66421534500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278575 (or 278560 counting only the distinct ones).

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

The spelling of 66421534500 in words is "sixty-six billion, four hundred twenty-one million, five hundred thirty-four thousand, five hundred".