28172499 has 4 divisors (see below), whose sum is σ = 37563336. Its totient is φ = 18781664.

The previous prime is 28172479. The next prime is 28172513. The reversal of 28172499 is 99427182.

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

It is a cyclic number.

It is not a de Polignac number, because 28172499 - 2¹¹ = 28170451 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28172499.

It is not an unprimeable number, because it can be changed into a prime (28172449) 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, 4695414 + ... + 4695419.

It is an arithmetic number, because the mean of its divisors is an integer number (9390834).

Almost surely, 2^28172499 is an apocalyptic number.

28172499 is a deficient number, since it is larger than the sum of its proper divisors (9390837).

28172499 is an equidigital number, since it uses as much as digits as its factorization.

28172499 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9390836.

The product of its digits is 72576, while the sum is 42.

The square root of 28172499 is about 5307.7772183844. Note that the first 3 decimals coincide. The cubic root of 28172499 is about 304.2812026108.

The spelling of 28172499 in words is "twenty-eight million, one hundred seventy-two thousand, four hundred ninety-nine".