1989643872 has 24 divisors (see below), whose sum is σ = 5222815416. Its totient is φ = 663214592.

The previous prime is 1989643847. The next prime is 1989643889. The reversal of 1989643872 is 2783469891.

It is a tau number, because it is divible by the number of its divisors (24).

It is a congruent number.

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, 10362633 + ... + 10362824.

It is an arithmetic number, because the mean of its divisors is an integer number (217617309).

Almost surely, 2^1989643872 is an apocalyptic number.

1989643872 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1989643872 is an abundant number, since it is smaller than the sum of its proper divisors (3233171544).

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

1989643872 is a wasteful number, since it uses less digits than its factorization.

1989643872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20725470 (or 20725462 counting only the distinct ones).

The product of its digits is 5225472, while the sum is 57.

The square root of 1989643872 is about 44605.4242441432. The cubic root of 1989643872 is about 1257.7426349560.

The spelling of 1989643872 in words is "one billion, nine hundred eighty-nine million, six hundred forty-three thousand, eight hundred seventy-two".