28520561 has 2 divisors, whose sum is σ = 28520562.
Its totient is φ = 28520560.
The previous prime is 28520551. The next prime is 28520579. The reversal of 28520561 is 16502582.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 27457600 + 1062961 = 5240^2 + 1031^2
It is a cyclic number.
It is not a de Polignac number, because 28520561 - 210 = 28519537 is a prime.
It is a Chen prime.
It is not a weakly prime, because it can be changed into another prime (28520521) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14260280 + 14260281.
It is an arithmetic number, because the mean of its divisors is an integer number (14260281).
Almost surely, 228520561 is an apocalyptic number.
It is an amenable number.
28520561 is a deficient number, since it is larger than the sum of its proper divisors (1).
28520561 is an equidigital number, since it uses as much as digits as its factorization.
28520561 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 4800, while the sum is 29.
The square root of 28520561 is about 5340.4644929070.
The cubic root of 28520561 is about 305.5291754097.
The spelling of 28520561 in words is "twenty-eight million, five hundred twenty thousand, five hundred sixty-one".