665243020800 has 1440 divisors, whose sum is σ = 2732769591552. Its totient is φ = 159411732480.

The previous prime is 665243020763. The next prime is 665243020829. The reversal of 665243020800 is 8020342566.

665243020800 is a `hidden beast` number, since 6 + 6 + 524 + 30 + 20 + 80 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1440).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 1216166127 + ... + 1216166673.

Almost surely, 2^665243020800 is an apocalyptic number.

665243020800 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 665243020800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1366384795776).

665243020800 is an abundant number, since it is smaller than the sum of its proper divisors (2067526570752).

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

665243020800 is a wasteful number, since it uses less digits than its factorization.

665243020800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630 (or 597 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The spelling of 665243020800 in words is "six hundred sixty-five billion, two hundred forty-three million, twenty thousand, eight hundred".