666974687744 has 80 divisors (see below), whose sum is σ = 1369503497208. Its totient is φ = 324275208192.

The previous prime is 666974687711. The next prime is 666974687759. The reversal of 666974687744 is 447786479666.

It can be written as a sum of positive squares in 4 ways, for example, as 496900927744 + 170073760000 = 704912^2 + 412400^2 .

It is a Harshad number since it is a multiple of its sum of digits (74).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33653582 + ... + 33673394.

Almost surely, 2^666974687744 is an apocalyptic number.

666974687744 is a gapful number since it is divisible by the number (64) 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 666974687744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (684751748604).

666974687744 is an abundant number, since it is smaller than the sum of its proper divisors (702528809464).

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

666974687744 is a wasteful number, since it uses less digits than its factorization.

666974687744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21645 (or 21629 counting only the distinct ones).

The product of its digits is 2048385024, while the sum is 74.

The spelling of 666974687744 in words is "six hundred sixty-six billion, nine hundred seventy-four million, six hundred eighty-seven thousand, seven hundred forty-four".