661987968000 has 704 divisors, whose sum is σ = 2375523521280. Its totient is φ = 163086336000.

The previous prime is 661987967983. The next prime is 661987968023. The reversal of 661987968000 is 869789166.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 299134894 + ... + 299137106.

Almost surely, 2^661987968000 is an apocalyptic number.

661987968000 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 661987968000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1187761760640).

661987968000 is an abundant number, since it is smaller than the sum of its proper divisors (1713535553280).

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

661987968000 is a wasteful number, since it uses less digits than its factorization.

661987968000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2311 (or 2283 counting only the distinct ones).

The product of its (nonzero) digits is 7838208, while the sum is 60.

The spelling of 661987968000 in words is "six hundred sixty-one billion, nine hundred eighty-seven million, nine hundred sixty-eight thousand".