28169521 has 2 divisors, whose sum is σ = 28169522. Its totient is φ = 28169520.

The previous prime is 28169507. The next prime is 28169539. The reversal of 28169521 is 12596182.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28037025 + 132496 = 5295^2 + 364^2 .

It is a cyclic number.

It is not a de Polignac number, because 28169521 - 2¹¹ = 28167473 is a prime.

It is not a weakly prime, because it can be changed into another prime (28169551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14084760 + 14084761.

It is an arithmetic number, because the mean of its divisors is an integer number (14084761).

Almost surely, 2^28169521 is an apocalyptic number.

It is an amenable number.

28169521 is a deficient number, since it is larger than the sum of its proper divisors (1).

28169521 is an equidigital number, since it uses as much as digits as its factorization.

28169521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 34.

The square root of 28169521 is about 5307.4966792265. The cubic root of 28169521 is about 304.2704807913.

The spelling of 28169521 in words is "twenty-eight million, one hundred sixty-nine thousand, five hundred twenty-one".