66813631040 has 336 divisors, whose sum is σ = 181536459888. Its totient is φ = 23279173632.

The previous prime is 66813630959. The next prime is 66813631057. The reversal of 66813631040 is 4013631866.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 24116847616 + 42696783424 = 155296^2 + 206632^2 .

It is a super-2 number, since 2×66813631040² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66813630985 and 66813631003.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 213461924 + ... + 213462236.

It is an arithmetic number, because the mean of its divisors is an integer number (540287083).

Almost surely, 2^66813631040 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66813631040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90768229944).

66813631040 is an abundant number, since it is smaller than the sum of its proper divisors (114722828848).

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

66813631040 is a wasteful number, since it uses less digits than its factorization.

66813631040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 486 (or 453 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 38.

The spelling of 66813631040 in words is "sixty-six billion, eight hundred thirteen million, six hundred thirty-one thousand, forty".