666979642560 has 1344 divisors, whose sum is σ = 2784501619200. Its totient is φ = 133668864000.

The previous prime is 666979642517. The next prime is 666979642573. The reversal of 666979642560 is 65246979666.

It is a tau number, because it is divible by the number of its divisors (1344).

It is a Harshad number since it is a multiple of its sum of digits (66).

It is a junction number, because it is equal to n+sod(n) for n = 666979642491 and 666979642500.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 3161040855 + ... + 3161041065.

It is an arithmetic number, because the mean of its divisors is an integer number (2071801800).

Almost surely, 2^666979642560 is an apocalyptic number.

666979642560 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 666979642560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1392250809600).

666979642560 is an abundant number, since it is smaller than the sum of its proper divisors (2117521976640).

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

666979642560 is a wasteful number, since it uses less digits than its factorization.

666979642560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446 (or 429 counting only the distinct ones).

The product of its (nonzero) digits is 176359680, while the sum is 66.

The spelling of 666979642560 in words is "six hundred sixty-six billion, nine hundred seventy-nine million, six hundred forty-two thousand, five hundred sixty".