28209997 has 2 divisors, whose sum is σ = 28209998. Its totient is φ = 28209996.

The previous prime is 28209989. The next prime is 28210001. The reversal of 28209997 is 79990282.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22762441 + 5447556 = 4771^2 + 2334^2 .

It is a cyclic number.

It is not a de Polignac number, because 28209997 - 2³ = 28209989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28209977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14104998 + 14104999.

It is an arithmetic number, because the mean of its divisors is an integer number (14104999).

Almost surely, 2^28209997 is an apocalyptic number.

It is an amenable number.

28209997 is a deficient number, since it is larger than the sum of its proper divisors (1).

28209997 is an equidigital number, since it uses as much as digits as its factorization.

28209997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 163296, while the sum is 46.

The square root of 28209997 is about 5311.3084075395. The cubic root of 28209997 is about 304.4161436398.

The spelling of 28209997 in words is "twenty-eight million, two hundred nine thousand, nine hundred ninety-seven".