28505261 has 2 divisors, whose sum is σ = 28505262. Its totient is φ = 28505260.

The previous prime is 28505251. The next prime is 28505329. The reversal of 28505261 is 16250582.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28249225 + 256036 = 5315^2 + 506^2 .

It is a cyclic number.

It is not a de Polignac number, because 28505261 - 2¹⁴ = 28488877 is a prime.

It is a Chen prime.

It is equal to p_1770932 and since 28505261 and 1770932 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28505251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14252630 + 14252631.

It is an arithmetic number, because the mean of its divisors is an integer number (14252631).

Almost surely, 2^28505261 is an apocalyptic number.

It is an amenable number.

28505261 is a deficient number, since it is larger than the sum of its proper divisors (1).

28505261 is an equidigital number, since it uses as much as digits as its factorization.

28505261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4800, while the sum is 29.

The square root of 28505261 is about 5339.0318410738. The cubic root of 28505261 is about 305.4745314105.

The spelling of 28505261 in words is "twenty-eight million, five hundred five thousand, two hundred sixty-one".