28601581 has 4 divisors (see below), whose sum is σ = 29845152. Its totient is φ = 27358012.

The previous prime is 28601567. The next prime is 28601603. The reversal of 28601581 is 18510682.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28601581 is a prime.

It is a super-2 number, since 2×28601581² = 1636100871399122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28601381) 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, 621751 + ... + 621796.

It is an arithmetic number, because the mean of its divisors is an integer number (7461288).

Almost surely, 2^28601581 is an apocalyptic number.

It is an amenable number.

28601581 is a deficient number, since it is larger than the sum of its proper divisors (1243571).

28601581 is a wasteful number, since it uses less digits than its factorization.

28601581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1243570.

The product of its (nonzero) digits is 3840, while the sum is 31.

The square root of 28601581 is about 5348.0445959248. The cubic root of 28601581 is about 305.8182133276.

The spelling of 28601581 in words is "twenty-eight million, six hundred one thousand, five hundred eighty-one".