28921171 has 4 divisors (see below), whose sum is σ = 29854144. Its totient is φ = 27988200.

The previous prime is 28921159. The next prime is 28921183. The reversal of 28921171 is 17112982.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (28921159) and next prime (28921183).

It is a cyclic number.

It is not a de Polignac number, because 28921171 - 2¹¹ = 28919123 is a prime.

It is a super-2 number, since 2×28921171² = 1672868264022482, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 932941 = 28921171 / (2 + 8 + 9 + 2 + 1 + 1 + 7 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28921141) 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, 466440 + ... + 466501.

It is an arithmetic number, because the mean of its divisors is an integer number (7463536).

Almost surely, 2^28921171 is an apocalyptic number.

28921171 is a deficient number, since it is larger than the sum of its proper divisors (932973).

28921171 is an equidigital number, since it uses as much as digits as its factorization.

28921171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 932972.

The product of its digits is 2016, while the sum is 31.

The square root of 28921171 is about 5377.8407376939. The cubic root of 28921171 is about 306.9530533312.

It can be divided in two parts, 28921 and 171, that added together give a palindrome (29092).

The spelling of 28921171 in words is "twenty-eight million, nine hundred twenty-one thousand, one hundred seventy-one".