28990989 has 12 divisors (see below), whose sum is σ = 41935036. Its totient is φ = 19300032.

The previous prime is 28990961. The next prime is 28990991. The reversal of 28990989 is 98909982.

It can be written as a sum of positive squares in 2 ways, for example, as 12320100 + 16670889 = 3510^2 + 4083^2 .

It is not a de Polignac number, because 28990989 - 2⁵ = 28990957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28990909) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6057 + ... + 9729.

Almost surely, 2^28990989 is an apocalyptic number.

It is an amenable number.

28990989 is a deficient number, since it is larger than the sum of its proper divisors (12944047).

28990989 is a wasteful number, since it uses less digits than its factorization.

28990989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4556 (or 4553 counting only the distinct ones).

The product of its (nonzero) digits is 839808, while the sum is 54.

The square root of 28990989 is about 5384.3280917864. The cubic root of 28990989 is about 307.1998578389.

The spelling of 28990989 in words is "twenty-eight million, nine hundred ninety thousand, nine hundred eighty-nine".