28129217 has 8 divisors (see below), whose sum is σ = 29164800. Its totient is φ = 27098064.

The previous prime is 28129201. The next prime is 28129223. The reversal of 28129217 is 71292182.

It is a happy number.

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

It is not a de Polignac number, because 28129217 - 2⁴ = 28129201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28129117) 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, 17168 + ... + 18734.

It is an arithmetic number, because the mean of its divisors is an integer number (3645600).

Almost surely, 2^28129217 is an apocalyptic number.

It is an amenable number.

28129217 is a deficient number, since it is larger than the sum of its proper divisors (1035583).

28129217 is a wasteful number, since it uses less digits than its factorization.

28129217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2215.

The product of its digits is 4032, while the sum is 32.

The square root of 28129217 is about 5303.6984265699. The cubic root of 28129217 is about 304.1252982166.

The spelling of 28129217 in words is "twenty-eight million, one hundred twenty-nine thousand, two hundred seventeen".