66181386240 has 312 divisors, whose sum is σ = 242906464008. Its totient is φ = 16609443840.

The previous prime is 66181386233. The next prime is 66181386269. The reversal of 66181386240 is 4268318166.

66181386240 is a `hidden beast` number, since 6 + 6 + 1 + 8 + 13 + 8 + 624 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 20515405824 + 45665980416 = 143232^2 + 213696^2 .

It is a super-2 number, since 2×66181386240² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

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, 3122880 + ... + 3144000.

It is an arithmetic number, because the mean of its divisors is an integer number (778546359).

Almost surely, 2^66181386240 is an apocalyptic number.

66181386240 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 66181386240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121453232004).

66181386240 is an abundant number, since it is smaller than the sum of its proper divisors (176725077768).

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

66181386240 is a wasteful number, since it uses less digits than its factorization.

66181386240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21173 (or 21148 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 45.

The spelling of 66181386240 in words is "sixty-six billion, one hundred eighty-one million, three hundred eighty-six thousand, two hundred forty".