665007378650640 has 480 divisors, whose sum is σ = 2263492012953600. Its totient is φ = 174956452070400.

The previous prime is 665007378650521. The next prime is 665007378650647. The reversal of 665007378650640 is 46056873700566.

665007378650640 is a `hidden beast` number, since 6 + 6 + 5 + 0 + 0 + 7 + 3 + 7 + 86 + 506 + 40 = 666.

It is not an unprimeable number, because it can be changed into a prime (665007378650647) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 24456879445 + ... + 24456906635.

It is an arithmetic number, because the mean of its divisors is an integer number (4715608360320).

Almost surely, 2^{665007378650640} is an apocalyptic number.

665007378650640 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 665007378650640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1131746006476800).

665007378650640 is an abundant number, since it is smaller than the sum of its proper divisors (1598484634302960).

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

665007378650640 is a wasteful number, since it uses less digits than its factorization.

665007378650640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28843 (or 28834 counting only the distinct ones).

The product of its (nonzero) digits is 152409600, while the sum is 63.

The spelling of 665007378650640 in words is "six hundred sixty-five trillion, seven billion, three hundred seventy-eight million, six hundred fifty thousand, six hundred forty".