28617521 has 2 divisors, whose sum is σ = 28617522. Its totient is φ = 28617520.

The previous prime is 28617517. The next prime is 28617527. The reversal of 28617521 is 12571682.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21669025 + 6948496 = 4655^2 + 2636^2 .

It is a cyclic number.

It is not a de Polignac number, because 28617521 - 2² = 28617517 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (28617527) 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, 14308760 + 14308761.

It is an arithmetic number, because the mean of its divisors is an integer number (14308761).

Almost surely, 2^28617521 is an apocalyptic number.

It is an amenable number.

28617521 is a deficient number, since it is larger than the sum of its proper divisors (1).

28617521 is an equidigital number, since it uses as much as digits as its factorization.

28617521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6720, while the sum is 32.

The square root of 28617521 is about 5349.5346526591. The cubic root of 28617521 is about 305.8750148148.

The spelling of 28617521 in words is "twenty-eight million, six hundred seventeen thousand, five hundred twenty-one".