28981789 has 4 divisors (see below), whose sum is σ = 29012256. Its totient is φ = 28951324.

The previous prime is 28981769. The next prime is 28981819. The reversal of 28981789 is 98718982.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28981789 - 2⁷ = 28981661 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 (28981709) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13759 + ... + 15724.

It is an arithmetic number, because the mean of its divisors is an integer number (7253064).

Almost surely, 2^28981789 is an apocalyptic number.

It is an amenable number.

28981789 is a deficient number, since it is larger than the sum of its proper divisors (30467).

28981789 is an equidigital number, since it uses as much as digits as its factorization.

28981789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30466.

The product of its digits is 580608, while the sum is 52.

The square root of 28981789 is about 5383.4736927007. The cubic root of 28981789 is about 307.1673588015.

The spelling of 28981789 in words is "twenty-eight million, nine hundred eighty-one thousand, seven hundred eighty-nine".