666516540 has 96 divisors (see below), whose sum is σ = 1954907136. Its totient is φ = 169354240.

The previous prime is 666516533. The next prime is 666516553. The reversal of 666516540 is 45615666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 428404 + ... + 429956.

It is an arithmetic number, because the mean of its divisors is an integer number (20363616).

Almost surely, 2^666516540 is an apocalyptic number.

666516540 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 666516540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (977453568).

666516540 is an abundant number, since it is smaller than the sum of its proper divisors (1288390596).

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

666516540 is a wasteful number, since it uses less digits than its factorization.

666516540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1899 (or 1897 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 39.

The square root of 666516540 is about 25816.9816206310. The cubic root of 666516540 is about 873.5148859519.

The spelling of 666516540 in words is "six hundred sixty-six million, five hundred sixteen thousand, five hundred forty".