28687889 has 2 divisors, whose sum is σ = 28687890. Its totient is φ = 28687888.

The previous prime is 28687861. The next prime is 28687909. The reversal of 28687889 is 98878682.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17850625 + 10837264 = 4225^2 + 3292^2 .

It is a cyclic number.

It is not a de Polignac number, because 28687889 - 2¹² = 28683793 is a prime.

It is not a weakly prime, because it can be changed into another prime (28687489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14343944 + 14343945.

It is an arithmetic number, because the mean of its divisors is an integer number (14343945).

Almost surely, 2^28687889 is an apocalyptic number.

It is an amenable number.

28687889 is a deficient number, since it is larger than the sum of its proper divisors (1).

28687889 is an equidigital number, since it uses as much as digits as its factorization.

28687889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3096576, while the sum is 56.

The square root of 28687889 is about 5356.1076352142. The cubic root of 28687889 is about 306.1255163097.

The spelling of 28687889 in words is "twenty-eight million, six hundred eighty-seven thousand, eight hundred eighty-nine".