28028561 has 12 divisors (see below), whose sum is σ = 31530576. Its totient is φ = 24883320.

The previous prime is 28028549. The next prime is 28028593. The reversal of 28028561 is 16582082.

It is a de Polignac number, because none of the positive numbers 2^k-28028561 is a prime.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28028501) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2510 + ... + 7896.

It is an arithmetic number, because the mean of its divisors is an integer number (2627548).

Almost surely, 2^28028561 is an apocalyptic number.

It is an amenable number.

28028561 is a deficient number, since it is larger than the sum of its proper divisors (3502015).

28028561 is a wasteful number, since it uses less digits than its factorization.

28028561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5452 (or 5441 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 28028561 is about 5294.2006951003. The cubic root of 28028561 is about 303.7621097421.

The spelling of 28028561 in words is "twenty-eight million, twenty-eight thousand, five hundred sixty-one".