28438291 has 4 divisors (see below), whose sum is σ = 32500912. Its totient is φ = 24375672.

The previous prime is 28438279. The next prime is 28438303. The reversal of 28438291 is 19283482.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19283482 = 2 ⋅9641741.

It is an interprime number because it is at equal distance from previous prime (28438279) and next prime (28438303).

It is a cyclic number.

It is not a de Polignac number, because 28438291 - 2¹⁵ = 28405523 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28438291.

It is not an unprimeable number, because it can be changed into a prime (28438211) 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, 2031300 + ... + 2031313.

It is an arithmetic number, because the mean of its divisors is an integer number (8125228).

Almost surely, 2^28438291 is an apocalyptic number.

28438291 is a deficient number, since it is larger than the sum of its proper divisors (4062621).

28438291 is an equidigital number, since it uses as much as digits as its factorization.

28438291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4062620.

The product of its digits is 27648, while the sum is 37.

The square root of 28438291 is about 5332.7564167136. The cubic root of 28438291 is about 305.2351174616.

The spelling of 28438291 in words is "twenty-eight million, four hundred thirty-eight thousand, two hundred ninety-one".