660857978880 has 896 divisors, whose sum is σ = 2599300549440. Its totient is φ = 159889489920.

The previous prime is 660857978863. The next prime is 660857978881. The reversal of 660857978880 is 88879758066.

660857978880 is a `hidden beast` number, since 6 + 608 + 5 + 7 + 9 + 7 + 8 + 8 + 8 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 660857978799 and 660857978808.

It is not an unprimeable number, because it can be changed into a prime (660857978881) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 1313832709 + ... + 1313833211.

Almost surely, 2^660857978880 is an apocalyptic number.

660857978880 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 660857978880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1299650274720).

660857978880 is an abundant number, since it is smaller than the sum of its proper divisors (1938442570560).

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

660857978880 is an frugal number, since it uses more digits than its factorization.

660857978880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 567 (or 524 counting only the distinct ones).

The product of its (nonzero) digits is 325140480, while the sum is 72.

The spelling of 660857978880 in words is "six hundred sixty billion, eight hundred fifty-seven million, nine hundred seventy-eight thousand, eight hundred eighty".