28158643 has 4 divisors (see below), whose sum is σ = 28193440. Its totient is φ = 28123848.

The previous prime is 28158617. The next prime is 28158649. The reversal of 28158643 is 34685182.

It is a happy number.

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 28158643 - 2²¹ = 26061491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28158649) 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, 16155 + ... + 17812.

It is an arithmetic number, because the mean of its divisors is an integer number (7048360).

Almost surely, 2^28158643 is an apocalyptic number.

28158643 is a deficient number, since it is larger than the sum of its proper divisors (34797).

28158643 is an equidigital number, since it uses as much as digits as its factorization.

28158643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34796.

The product of its digits is 46080, while the sum is 37.

The square root of 28158643 is about 5306.4718033737. The cubic root of 28158643 is about 304.2313098444.

The spelling of 28158643 in words is "twenty-eight million, one hundred fifty-eight thousand, six hundred forty-three".