666681570 has 64 divisors (see below), whose sum is σ = 1781136000. Its totient is φ = 177450048.

The previous prime is 666681569. The next prime is 666681649. The reversal of 666681570 is 75186666.

666681570 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 165136 + ... + 169124.

It is an arithmetic number, because the mean of its divisors is an integer number (27830250).

Almost surely, 2^666681570 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666681570, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (890568000).

666681570 is an abundant number, since it is smaller than the sum of its proper divisors (1114454430).

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

666681570 is a wasteful number, since it uses less digits than its factorization.

666681570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4624 (or 4618 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The square root of 666681570 is about 25820.1775749122. The cubic root of 666681570 is about 873.5869743182.

The spelling of 666681570 in words is "six hundred sixty-six million, six hundred eighty-one thousand, five hundred seventy".