1668020644 has 12 divisors (see below), whose sum is σ = 2928546544. Its totient is φ = 831293064.

The previous prime is 1668020639. The next prime is 1668020699. The reversal of 1668020644 is 4460208661.

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 677934 + ... + 680389.

Almost surely, 2^1668020644 is an apocalyptic number.

It is an amenable number.

1668020644 is a deficient number, since it is larger than the sum of its proper divisors (1260525900).

1668020644 is a wasteful number, since it uses less digits than its factorization.

1668020644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1358634 (or 1358632 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 37.

The square root of 1668020644 is about 40841.4084477996. The cubic root of 1668020644 is about 1185.9520781208.

The spelling of 1668020644 in words is "one billion, six hundred sixty-eight million, twenty thousand, six hundred forty-four".