28285028561 has 4 divisors (see below), whose sum is σ = 28352214324. Its totient is φ = 28217842800.

The previous prime is 28285028557. The next prime is 28285028567. The reversal of 28285028561 is 16582058282.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16582058282 = 2 ⋅8291029141.

It can be written as a sum of positive squares in 2 ways, for example, as 8881931536 + 19403097025 = 94244^2 + 139295^2 .

It is a cyclic number.

It is not a de Polignac number, because 28285028561 - 2² = 28285028557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28285028567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33592250 + ... + 33593091.

It is an arithmetic number, because the mean of its divisors is an integer number (7088053581).

Almost surely, 2^28285028561 is an apocalyptic number.

It is an amenable number.

28285028561 is a deficient number, since it is larger than the sum of its proper divisors (67185763).

28285028561 is an equidigital number, since it uses as much as digits as its factorization.

28285028561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67185762.

The product of its (nonzero) digits is 614400, while the sum is 47.

The spelling of 28285028561 in words is "twenty-eight billion, two hundred eighty-five million, twenty-eight thousand, five hundred sixty-one".