666751206400 has 198 divisors, whose sum is σ = 1755693628478. Its totient is φ = 251009433600.

The previous prime is 666751206379. The next prime is 666751206439. The reversal of 666751206400 is 4602157666.

It is a happy number.

It can be written as a sum of positive squares in 9 ways, for example, as 9069133824 + 657682072576 = 95232^2 + 810976^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 7353340 + ... + 7443460.

Almost surely, 2^666751206400 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 666751206400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (877846814239).

666751206400 is an abundant number, since it is smaller than the sum of its proper divisors (1088942422078).

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

666751206400 is a wasteful number, since it uses less digits than its factorization.

666751206400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90185 (or 90145 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 43.

The spelling of 666751206400 in words is "six hundred sixty-six billion, seven hundred fifty-one million, two hundred six thousand, four hundred".