28431889 has 2 divisors, whose sum is σ = 28431890. Its totient is φ = 28431888.

The previous prime is 28431881. The next prime is 28431911. The reversal of 28431889 is 98813482.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16646400 + 11785489 = 4080^2 + 3433^2 .

It is a cyclic number.

It is not a de Polignac number, because 28431889 - 2³ = 28431881 is a prime.

It is not a weakly prime, because it can be changed into another prime (28431881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14215944 + 14215945.

It is an arithmetic number, because the mean of its divisors is an integer number (14215945).

Almost surely, 2^28431889 is an apocalyptic number.

It is an amenable number.

28431889 is a deficient number, since it is larger than the sum of its proper divisors (1).

28431889 is an equidigital number, since it uses as much as digits as its factorization.

28431889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 110592, while the sum is 43.

The square root of 28431889 is about 5332.1561304973. The cubic root of 28431889 is about 305.2122109999.

The spelling of 28431889 in words is "twenty-eight million, four hundred thirty-one thousand, eight hundred eighty-nine".