28211021 has 2 divisors, whose sum is σ = 28211022. Its totient is φ = 28211020.

The previous prime is 28211009. The next prime is 28211033. The reversal of 28211021 is 12011282.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (28211009) and next prime (28211033).

It can be written as a sum of positive squares in only one way, i.e., 27678121 + 532900 = 5261^2 + 730^2 .

It is a cyclic number.

It is not a de Polignac number, because 28211021 - 2¹⁰ = 28209997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28211081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14105510 + 14105511.

It is an arithmetic number, because the mean of its divisors is an integer number (14105511).

Almost surely, 2^28211021 is an apocalyptic number.

It is an amenable number.

28211021 is a deficient number, since it is larger than the sum of its proper divisors (1).

28211021 is an equidigital number, since it uses as much as digits as its factorization.

28211021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 28211021 is about 5311.4048047574. The cubic root of 28211021 is about 304.4198269482.

The spelling of 28211021 in words is "twenty-eight million, two hundred eleven thousand, twenty-one".