28227821 has 2 divisors, whose sum is σ = 28227822. Its totient is φ = 28227820.

The previous prime is 28227799. The next prime is 28227841. The reversal of 28227821 is 12872282.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26574025 + 1653796 = 5155^2 + 1286^2 .

It is a cyclic number.

It is not a de Polignac number, because 28227821 - 2¹⁰ = 28226797 is a prime.

It is equal to p_1754717 and since 28227821 and 1754717 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28227841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14113910 + 14113911.

It is an arithmetic number, because the mean of its divisors is an integer number (14113911).

Almost surely, 2^28227821 is an apocalyptic number.

It is an amenable number.

28227821 is a deficient number, since it is larger than the sum of its proper divisors (1).

28227821 is an equidigital number, since it uses as much as digits as its factorization.

28227821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7168, while the sum is 32.

The square root of 28227821 is about 5312.9860718809. The cubic root of 28227821 is about 304.4802435047.

The spelling of 28227821 in words is "twenty-eight million, two hundred twenty-seven thousand, eight hundred twenty-one".