28999989 has 6 divisors (see below), whose sum is σ = 41888886. Its totient is φ = 19333320.

The previous prime is 28999979. The next prime is 28999991. The reversal of 28999989 is 98999982.

It can be written as a sum of positive squares in only one way, i.e., 28998225 + 1764 = 5385^2 + 42^2 .

It is not a de Polignac number, because 28999989 - 2¹⁶ = 28934453 is a prime.

It is a super-5 number, since 5×28999989⁵ (a number of 39 digits) contains 55555 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28999939) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1611102 + ... + 1611119.

It is an arithmetic number, because the mean of its divisors is an integer number (6981481).

Almost surely, 2^28999989 is an apocalyptic number.

It is an amenable number.

28999989 is a deficient number, since it is larger than the sum of its proper divisors (12888897).

28999989 is a wasteful number, since it uses less digits than its factorization.

28999989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3222227 (or 3222224 counting only the distinct ones).

The product of its digits is 7558272, while the sum is 63.

The square root of 28999989 is about 5385.1637858100. The cubic root of 28999989 is about 307.2316437232.

The spelling of 28999989 in words is "twenty-eight million, nine hundred ninety-nine thousand, nine hundred eighty-nine".