28745989 has 8 divisors (see below), whose sum is σ = 29799000. Its totient is φ = 27697152.

The previous prime is 28745987. The next prime is 28746037. The reversal of 28745989 is 98954782.

It can be written as a sum of positive squares in 4 ways, for example, as 7049025 + 21696964 = 2655^2 + 4658^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28745989 - 2¹ = 28745987 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 (28745987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21657 + ... + 22945.

It is an arithmetic number, because the mean of its divisors is an integer number (3724875).

Almost surely, 2^28745989 is an apocalyptic number.

28745989 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

28745989 is a deficient number, since it is larger than the sum of its proper divisors (1053011).

28745989 is a wasteful number, since it uses less digits than its factorization.

28745989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2087.

The product of its digits is 1451520, while the sum is 52.

The square root of 28745989 is about 5361.5286066569. The cubic root of 28745989 is about 306.3320366647.

The spelling of 28745989 in words is "twenty-eight million, seven hundred forty-five thousand, nine hundred eighty-nine".