28180865 has 24 divisors (see below), whose sum is σ = 36469440. Its totient is φ = 20864448.

The previous prime is 28180811. The next prime is 28180879. The reversal of 28180865 is 56808182.

It is not a de Polignac number, because 28180865 - 2¹⁸ = 27918721 is a prime.

It is a super-2 number, since 2×28180865² = 1588322304296450, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 157346 + ... + 157524.

It is an arithmetic number, because the mean of its divisors is an integer number (1519560).

Almost surely, 2^28180865 is an apocalyptic number.

It is an amenable number.

28180865 is a deficient number, since it is larger than the sum of its proper divisors (8288575).

28180865 is a wasteful number, since it uses less digits than its factorization.

28180865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 281 (or 244 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 38.

The square root of 28180865 is about 5308.5652487278. The cubic root of 28180865 is about 304.3113190328.

The spelling of 28180865 in words is "twenty-eight million, one hundred eighty thousand, eight hundred sixty-five".