28157439 has 4 divisors (see below), whose sum is σ = 37543256. Its totient is φ = 18771624.

The previous prime is 28157429. The next prime is 28157461. The reversal of 28157439 is 93475182.

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

It is not a de Polignac number, because 28157439 - 2⁹ = 28156927 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28157397 and 28157406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28157429) 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, 4692904 + ... + 4692909.

It is an arithmetic number, because the mean of its divisors is an integer number (9385814).

Almost surely, 2^28157439 is an apocalyptic number.

28157439 is a deficient number, since it is larger than the sum of its proper divisors (9385817).

28157439 is an equidigital number, since it uses as much as digits as its factorization.

28157439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9385816.

The product of its digits is 60480, while the sum is 39.

The square root of 28157439 is about 5306.3583557841. The cubic root of 28157439 is about 304.2269737013.

The spelling of 28157439 in words is "twenty-eight million, one hundred fifty-seven thousand, four hundred thirty-nine".