28288639 has 2 divisors, whose sum is σ = 28288640. Its totient is φ = 28288638.

The previous prime is 28288621. The next prime is 28288657. The reversal of 28288639 is 93688282.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (28288621) and next prime (28288657).

It is a cyclic number.

It is not a de Polignac number, because 28288639 - 2⁵ = 28288607 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28288619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14144319 + 14144320.

It is an arithmetic number, because the mean of its divisors is an integer number (14144320).

Almost surely, 2^28288639 is an apocalyptic number.

28288639 is a deficient number, since it is larger than the sum of its proper divisors (1).

28288639 is an equidigital number, since it uses as much as digits as its factorization.

28288639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 331776, while the sum is 46.

The square root of 28288639 is about 5318.7065156859. The cubic root of 28288639 is about 304.6987583778.

It can be divided in two parts, 2 and 8288639, that added together give a square (8288641 = 2879²).

The spelling of 28288639 in words is "twenty-eight million, two hundred eighty-eight thousand, six hundred thirty-nine".