28939231 has 2 divisors, whose sum is σ = 28939232. Its totient is φ = 28939230.

The previous prime is 28939199. The next prime is 28939259. The reversal of 28939231 is 13293982.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28939231 - 2⁵ = 28939199 is a prime.

It is a super-2 number, since 2×28939231² = 1674958181742722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28939331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14469615 + 14469616.

It is an arithmetic number, because the mean of its divisors is an integer number (14469616).

Almost surely, 2^28939231 is an apocalyptic number.

28939231 is a deficient number, since it is larger than the sum of its proper divisors (1).

28939231 is an equidigital number, since it uses as much as digits as its factorization.

28939231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23328, while the sum is 37.

The square root of 28939231 is about 5379.5195882160. The cubic root of 28939231 is about 307.0169329327.

The spelling of 28939231 in words is "twenty-eight million, nine hundred thirty-nine thousand, two hundred thirty-one".