1666606644 has 96 divisors (see below), whose sum is σ = 4414851840. Its totient is φ = 543573504.

The previous prime is 1666606639. The next prime is 1666606687. The reversal of 1666606644 is 4466066661.

It is a self number, because there is not a number n which added to its sum of digits gives 1666606644.

It is a congruent number.

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, 1079337 + ... + 1080879.

It is an arithmetic number, because the mean of its divisors is an integer number (45988040).

Almost surely, 2^1666606644 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1666606644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2207425920).

1666606644 is an abundant number, since it is smaller than the sum of its proper divisors (2748245196).

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

1666606644 is a wasteful number, since it uses less digits than its factorization.

1666606644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1766 (or 1758 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 45.

The square root of 1666606644 is about 40824.0939152359. The cubic root of 1666606644 is about 1185.6168683777.

The spelling of 1666606644 in words is "one billion, six hundred sixty-six million, six hundred six thousand, six hundred forty-four".