66813258829680 has 400 divisors, whose sum is σ = 253514551137408. Its totient is φ = 16173701568000.

The previous prime is 66813258829673. The next prime is 66813258829699. The reversal of 66813258829680 is 8692885231866.

66813258829680 is a `hidden beast` number, since 6 + 6 + 8 + 1 + 3 + 258 + 8 + 296 + 80 = 666.

It is a Smith number, since the sum of its digits (72) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 66813258829599 and 66813258829608.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 48576235 + ... + 49932725.

Almost surely, 2^{66813258829680} is an apocalyptic number.

66813258829680 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 66813258829680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126757275568704).

66813258829680 is an abundant number, since it is smaller than the sum of its proper divisors (186701292307728).

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

66813258829680 is a wasteful number, since it uses less digits than its factorization.

66813258829680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1357218 (or 1357203 counting only the distinct ones).

The product of its (nonzero) digits is 477757440, while the sum is 72.

The spelling of 66813258829680 in words is "sixty-six trillion, eight hundred thirteen billion, two hundred fifty-eight million, eight hundred twenty-nine thousand, six hundred eighty".