28869581 has 8 divisors (see below), whose sum is σ = 31214904. Its totient is φ = 26542080.

The previous prime is 28869559. The next prime is 28869593. The reversal of 28869581 is 18596882.

It can be written as a sum of positive squares in 4 ways, for example, as 1359556 + 27510025 = 1166^2 + 5245^2 .

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 28869581 - 2⁶ = 28869517 is a prime.

It is a super-2 number, since 2×28869581² = 1666905414231122, 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 (28869551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 980 + ... + 7661.

It is an arithmetic number, because the mean of its divisors is an integer number (3901863).

Almost surely, 2^28869581 is an apocalyptic number.

It is an amenable number.

28869581 is a deficient number, since it is larger than the sum of its proper divisors (2345323).

28869581 is a wasteful number, since it uses less digits than its factorization.

28869581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8911.

The product of its digits is 276480, while the sum is 47.

The square root of 28869581 is about 5373.0420619980. The cubic root of 28869581 is about 306.7704289444.

It can be divided in two parts, 2886 and 9581, that multiplied together give a triangular number (27650766 = T₇₄₃₆).

The spelling of 28869581 in words is "twenty-eight million, eight hundred sixty-nine thousand, five hundred eighty-one".