28274921 has 2 divisors, whose sum is σ = 28274922. Its totient is φ = 28274920.

The previous prime is 28274887. The next prime is 28274923. The reversal of 28274921 is 12947282.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26677225 + 1597696 = 5165^2 + 1264^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28274921 is a prime.

Together with 28274923, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_1757483 and since 28274921 and 1757483 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (28274923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14137460 + 14137461.

It is an arithmetic number, because the mean of its divisors is an integer number (14137461).

Almost surely, 2^28274921 is an apocalyptic number.

It is an amenable number.

28274921 is a deficient number, since it is larger than the sum of its proper divisors (1).

28274921 is an equidigital number, since it uses as much as digits as its factorization.

28274921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16128, while the sum is 35.

The square root of 28274921 is about 5317.4167600443. The cubic root of 28274921 is about 304.6494979262.

The spelling of 28274921 in words is "twenty-eight million, two hundred seventy-four thousand, nine hundred twenty-one".