28172989 has 8 divisors (see below), whose sum is σ = 30512160. Its totient is φ = 25858416.

The previous prime is 28172987. The next prime is 28173001. The reversal of 28172989 is 98927182.

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 28172989 - 2¹ = 28172987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28172983) 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, 3727 + ... + 8380.

It is an arithmetic number, because the mean of its divisors is an integer number (3814020).

Almost surely, 2^28172989 is an apocalyptic number.

It is an amenable number.

28172989 is a deficient number, since it is larger than the sum of its proper divisors (2339171).

28172989 is a wasteful number, since it uses less digits than its factorization.

28172989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12299.

The product of its digits is 145152, while the sum is 46.

The square root of 28172989 is about 5307.8233768655. The cubic root of 28172989 is about 304.2829667062.

It can be divided in two parts, 28172 and 989, that added together give a triangular number (29161 = T₂₄₁).

The spelling of 28172989 in words is "twenty-eight million, one hundred seventy-two thousand, nine hundred eighty-nine".