28205231 has 2 divisors, whose sum is σ = 28205232. Its totient is φ = 28205230.

The previous prime is 28205189. The next prime is 28205237. The reversal of 28205231 is 13250282.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28205231 is a prime.

It is a super-2 number, since 2×28205231² = 1591070111526722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28205197 and 28205206.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28205237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14102615 + 14102616.

It is an arithmetic number, because the mean of its divisors is an integer number (14102616).

Almost surely, 2^28205231 is an apocalyptic number.

28205231 is a deficient number, since it is larger than the sum of its proper divisors (1).

28205231 is an equidigital number, since it uses as much as digits as its factorization.

28205231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 28205231 is about 5310.8597232463. The cubic root of 28205231 is about 304.3989992559.

The spelling of 28205231 in words is "twenty-eight million, two hundred five thousand, two hundred thirty-one".