28309121 has 2 divisors, whose sum is σ = 28309122. Its totient is φ = 28309120.

The previous prime is 28309117. The next prime is 28309129. The reversal of 28309121 is 12190382.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28206721 + 102400 = 5311^2 + 320^2 .

It is a cyclic number.

It is not a de Polignac number, because 28309121 - 2² = 28309117 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28309129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14154560 + 14154561.

It is an arithmetic number, because the mean of its divisors is an integer number (14154561).

Almost surely, 2^28309121 is an apocalyptic number.

It is an amenable number.

28309121 is a deficient number, since it is larger than the sum of its proper divisors (1).

28309121 is an equidigital number, since it uses as much as digits as its factorization.

28309121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 28309121 is about 5320.6316354358. The cubic root of 28309121 is about 304.7722782854.

The spelling of 28309121 in words is "twenty-eight million, three hundred nine thousand, one hundred twenty-one".