660771820800 has 3888 divisors, whose sum is σ = 3312984205440. Its totient is φ = 128755630080.

The previous prime is 660771820759. The next prime is 660771820801. The reversal of 660771820800 is 8028177066.

660771820800 is a `hidden beast` number, since 6 + 607 + 7 + 18 + 20 + 8 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (3888).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660771820801) by changing a digit.

It is a polite number, since it can be written in 431 ways as a sum of consecutive naturals, for example, 22785235186 + ... + 22785235214.

Almost surely, 2^660771820800 is an apocalyptic number.

660771820800 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 660771820800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1656492102720).

660771820800 is an abundant number, since it is smaller than the sum of its proper divisors (2652212384640).

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

660771820800 is a wasteful number, since it uses less digits than its factorization.

660771820800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120 (or 82 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 45.

Adding to 660771820800 its reverse (8028177066), we get a palindrome (668799997866).

The spelling of 660771820800 in words is "six hundred sixty billion, seven hundred seventy-one million, eight hundred twenty thousand, eight hundred".