28265821 has 2 divisors, whose sum is σ = 28265822. Its totient is φ = 28265820.

The previous prime is 28265803. The next prime is 28265833. The reversal of 28265821 is 12856282.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28238596 + 27225 = 5314^2 + 165^2 .

It is a cyclic number.

It is not a de Polignac number, because 28265821 - 2⁷ = 28265693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28265221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14132910 + 14132911.

It is an arithmetic number, because the mean of its divisors is an integer number (14132911).

Almost surely, 2^28265821 is an apocalyptic number.

It is an amenable number.

28265821 is a deficient number, since it is larger than the sum of its proper divisors (1).

28265821 is an equidigital number, since it uses as much as digits as its factorization.

28265821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15360, while the sum is 34.

The square root of 28265821 is about 5316.5610125343. The cubic root of 28265821 is about 304.6168116233.

The spelling of 28265821 in words is "twenty-eight million, two hundred sixty-five thousand, eight hundred twenty-one".