28228639 has 2 divisors, whose sum is σ = 28228640. Its totient is φ = 28228638.

The previous prime is 28228621. The next prime is 28228663. The reversal of 28228639 is 93682282.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28228639 - 2⁹ = 28228127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28220639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14114319 + 14114320.

It is an arithmetic number, because the mean of its divisors is an integer number (14114320).

Almost surely, 2^28228639 is an apocalyptic number.

28228639 is a deficient number, since it is larger than the sum of its proper divisors (1).

28228639 is an equidigital number, since it uses as much as digits as its factorization.

28228639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 82944, while the sum is 40.

The square root of 28228639 is about 5313.0630525150. The cubic root of 28228639 is about 304.4831846035.

The spelling of 28228639 in words is "twenty-eight million, two hundred twenty-eight thousand, six hundred thirty-nine".