28056581 has 8 divisors (see below), whose sum is σ = 33099264. Its totient is φ = 23272560.

The previous prime is 28056569. The next prime is 28056583. The reversal of 28056581 is 18565082.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28056581 - 2⁶ = 28056517 is a prime.

It is a super-2 number, since 2×28056581² = 1574343474819122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28056583) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 64430 + ... + 64863.

It is an arithmetic number, because the mean of its divisors is an integer number (4137408).

Almost surely, 2^28056581 is an apocalyptic number.

It is an amenable number.

28056581 is a deficient number, since it is larger than the sum of its proper divisors (5042683).

28056581 is a wasteful number, since it uses less digits than its factorization.

28056581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129331.

The product of its (nonzero) digits is 19200, while the sum is 35.

The square root of 28056581 is about 5296.8463258811. The cubic root of 28056581 is about 303.8632991397.

The spelling of 28056581 in words is "twenty-eight million, fifty-six thousand, five hundred eighty-one".