28021237 has 2 divisors, whose sum is σ = 28021238. Its totient is φ = 28021236.

The previous prime is 28021207. The next prime is 28021249. The reversal of 28021237 is 73212082.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23415921 + 4605316 = 4839^2 + 2146^2 .

It is a cyclic number.

It is not a de Polignac number, because 28021237 - 2⁷ = 28021109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28021207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14010618 + 14010619.

It is an arithmetic number, because the mean of its divisors is an integer number (14010619).

Almost surely, 2^28021237 is an apocalyptic number.

It is an amenable number.

28021237 is a deficient number, since it is larger than the sum of its proper divisors (1).

28021237 is an equidigital number, since it uses as much as digits as its factorization.

28021237 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 28021237 is about 5293.5089496477. The cubic root of 28021237 is about 303.7356492625.

The spelling of 28021237 in words is "twenty-eight million, twenty-one thousand, two hundred thirty-seven".