28208493 has 10 divisors (see below), whose sum is σ = 42138734. Its totient is φ = 18805608.

The previous prime is 28208489. The next prime is 28208539. The reversal of 28208493 is 39480282.

It can be written as a sum of positive squares in only one way, i.e., 20820969 + 7387524 = 4563^2 + 2718^2 .

It is not a de Polignac number, because 28208493 - 2² = 28208489 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 (28208443) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 174046 + ... + 174207.

Almost surely, 2^28208493 is an apocalyptic number.

It is an amenable number.

28208493 is a deficient number, since it is larger than the sum of its proper divisors (13930241).

28208493 is an equidigital number, since it uses as much as digits as its factorization.

28208493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 348265 (or 348256 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 28208493 is about 5311.1668209538. The cubic root of 28208493 is about 304.4107336190.

The spelling of 28208493 in words is "twenty-eight million, two hundred eight thousand, four hundred ninety-three".