28286391 has 8 divisors (see below), whose sum is σ = 43103104. Its totient is φ = 16163640.

The previous prime is 28286369. The next prime is 28286393. The reversal of 28286391 is 19368282.

It is a happy number.

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

It is not a de Polignac number, because 28286391 - 2⁵ = 28286359 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28286393) 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, 673465 + ... + 673506.

It is an arithmetic number, because the mean of its divisors is an integer number (5387888).

Almost surely, 2^28286391 is an apocalyptic number.

28286391 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

28286391 is a deficient number, since it is larger than the sum of its proper divisors (14816713).

28286391 is a wasteful number, since it uses less digits than its factorization.

28286391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1346981.

The product of its digits is 41472, while the sum is 39.

The square root of 28286391 is about 5318.4951819100. The cubic root of 28286391 is about 304.6906870462.

The spelling of 28286391 in words is "twenty-eight million, two hundred eighty-six thousand, three hundred ninety-one".