1989943281 has 56 divisors (see below), whose sum is σ = 3079015976. Its totient is φ = 1284906240.

The previous prime is 1989943273. The next prime is 1989943297. The reversal of 1989943281 is 1823499891.

It can be written as a sum of positive squares in 4 ways, for example, as 112021056 + 1877922225 = 10584^2 + 43335^2 .

It is not a de Polignac number, because 1989943281 - 2³ = 1989943273 is a prime.

It is a super-2 number, since 2×1989943281² = 7919748523194089922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1989943201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 3245931 + ... + 3246543.

Almost surely, 2^1989943281 is an apocalyptic number.

It is an amenable number.

1989943281 is a deficient number, since it is larger than the sum of its proper divisors (1089072695).

1989943281 is an frugal number, since it uses more digits than its factorization.

1989943281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 765 (or 750 counting only the distinct ones).

The product of its digits is 1119744, while the sum is 54.

The square root of 1989943281 is about 44608.7803128487. The cubic root of 1989943281 is about 1257.8057217194.

The spelling of 1989943281 in words is "one billion, nine hundred eighty-nine million, nine hundred forty-three thousand, two hundred eighty-one".