28561806 has 144 divisors (see below), whose sum is σ = 80668224. Its totient is φ = 7233408.

The previous prime is 28561787. The next prime is 28561823. The reversal of 28561806 is 60816582.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 538876 + ... + 538928.

It is an arithmetic number, because the mean of its divisors is an integer number (560196).

Almost surely, 2^28561806 is an apocalyptic number.

28561806 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 28561806, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40334112).

28561806 is an abundant number, since it is smaller than the sum of its proper divisors (52106418).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28561806 is a wasteful number, since it uses less digits than its factorization.

28561806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135 (or 125 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 28561806 is about 5344.3246533121. The cubic root of 28561806 is about 305.6763847761.

The spelling of 28561806 in words is "twenty-eight million, five hundred sixty-one thousand, eight hundred six".