28499391 has 16 divisors (see below), whose sum is σ = 42599520. Its totient is φ = 18829440.

The previous prime is 28499389. The next prime is 28499407. The reversal of 28499391 is 19399482.

It is not a de Polignac number, because 28499391 - 2¹ = 28499389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28499311) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1620 + ... + 7721.

It is an arithmetic number, because the mean of its divisors is an integer number (2662470).

Almost surely, 2^28499391 is an apocalyptic number.

28499391 is a deficient number, since it is larger than the sum of its proper divisors (14100129).

28499391 is a wasteful number, since it uses less digits than its factorization.

28499391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9463 (or 9457 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 28499391 is about 5338.4820876350. The cubic root of 28499391 is about 305.4535614967.

Subtracting from 28499391 its reverse (19399482), we obtain a palindrome (9099909).

The spelling of 28499391 in words is "twenty-eight million, four hundred ninety-nine thousand, three hundred ninety-one".