28370521 has 2 divisors, whose sum is σ = 28370522. Its totient is φ = 28370520.

The previous prime is 28370519. The next prime is 28370533. The reversal of 28370521 is 12507382.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28302400 + 68121 = 5320^2 + 261^2 .

It is a cyclic number.

It is not a de Polignac number, because 28370521 - 2¹ = 28370519 is a prime.

It is a super-2 number, since 2×28370521² = 1609772923622882, which contains 22 as substring.

Together with 28370519, it forms a pair of twin primes.

It is equal to p_1763056 and since 28370521 and 1763056 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28370521.

It is not a weakly prime, because it can be changed into another prime (28370621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14185260 + 14185261.

It is an arithmetic number, because the mean of its divisors is an integer number (14185261).

Almost surely, 2^28370521 is an apocalyptic number.

It is an amenable number.

28370521 is a deficient number, since it is larger than the sum of its proper divisors (1).

28370521 is an equidigital number, since it uses as much as digits as its factorization.

28370521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 28370521 is about 5326.3985018021. The cubic root of 28370521 is about 304.9924606217.

The spelling of 28370521 in words is "twenty-eight million, three hundred seventy thousand, five hundred twenty-one".