1989397566 has 48 divisors (see below), whose sum is σ = 4645184544. Its totient is φ = 611692992.

The previous prime is 1989397523. The next prime is 1989397583. The reversal of 1989397566 is 6657939891.

1989397566 is a `hidden beast` number, since 198 + 9 + 397 + 56 + 6 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 549735 + ... + 553341.

It is an arithmetic number, because the mean of its divisors is an integer number (96774678).

Almost surely, 2^1989397566 is an apocalyptic number.

1989397566 is an abundant number, since it is smaller than the sum of its proper divisors (2655786978).

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

1989397566 is a wasteful number, since it uses less digits than its factorization.

1989397566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5985 (or 5982 counting only the distinct ones).

The product of its digits is 22044960, while the sum is 63.

The square root of 1989397566 is about 44602.6632164493. The cubic root of 1989397566 is about 1257.6907324780.

The spelling of 1989397566 in words is "one billion, nine hundred eighty-nine million, three hundred ninety-seven thousand, five hundred sixty-six".