28153643 has 4 divisors (see below), whose sum is σ = 32175600. Its totient is φ = 24131688.

The previous prime is 28153639. The next prime is 28153661. The reversal of 28153643 is 34635182.

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

It is not a de Polignac number, because 28153643 - 2² = 28153639 is a prime.

It is a super-2 number, since 2×28153643² = 1585255228342898, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28153663) 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, 2010968 + ... + 2010981.

It is an arithmetic number, because the mean of its divisors is an integer number (8043900).

Almost surely, 2^28153643 is an apocalyptic number.

28153643 is a deficient number, since it is larger than the sum of its proper divisors (4021957).

28153643 is an equidigital number, since it uses as much as digits as its factorization.

28153643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4021956.

The product of its digits is 17280, while the sum is 32.

The square root of 28153643 is about 5306.0006596306. Note that the first 3 decimals coincide. The cubic root of 28153643 is about 304.2133017963.

The spelling of 28153643 in words is "twenty-eight million, one hundred fifty-three thousand, six hundred forty-three".