28222021 has 2 divisors, whose sum is σ = 28222022. Its totient is φ = 28222020.

The previous prime is 28221971. The next prime is 28222031. The reversal of 28222021 is 12022282.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28196100 + 25921 = 5310^2 + 161^2 .

It is a cyclic number.

It is not a de Polignac number, because 28222021 - 2⁹ = 28221509 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28222021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28222031) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14111010 + 14111011.

It is an arithmetic number, because the mean of its divisors is an integer number (14111011).

Almost surely, 2^28222021 is an apocalyptic number.

It is an amenable number.

28222021 is a deficient number, since it is larger than the sum of its proper divisors (1).

28222021 is an equidigital number, since it uses as much as digits as its factorization.

28222021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 28222021 is about 5312.4402114283. The cubic root of 28222021 is about 304.4593881179.

The spelling of 28222021 in words is "twenty-eight million, two hundred twenty-two thousand, twenty-one".