28691143 has 8 divisors (see below), whose sum is σ = 32241888. Its totient is φ = 25332384.

The previous prime is 28691137. The next prime is 28691153. The reversal of 28691143 is 34119682.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28691143 - 2²¹ = 26593991 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28691099 and 28691108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28691123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47680 + ... + 48277.

It is an arithmetic number, because the mean of its divisors is an integer number (4030236).

Almost surely, 2^28691143 is an apocalyptic number.

28691143 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

28691143 is a deficient number, since it is larger than the sum of its proper divisors (3550745).

28691143 is a wasteful number, since it uses less digits than its factorization.

28691143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95993.

The product of its digits is 10368, while the sum is 34.

The square root of 28691143 is about 5356.4113919676. The cubic root of 28691143 is about 306.1370902387.

The spelling of 28691143 in words is "twenty-eight million, six hundred ninety-one thousand, one hundred forty-three".