28628231 has 4 divisors (see below), whose sum is σ = 30135000. Its totient is φ = 27121464.

The previous prime is 28628219. The next prime is 28628233. The reversal of 28628231 is 13282682.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28628231 is a prime.

It is a super-2 number, since 2×28628231² = 1639151220378722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28628233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 753356 + ... + 753393.

It is an arithmetic number, because the mean of its divisors is an integer number (7533750).

Almost surely, 2^28628231 is an apocalyptic number.

28628231 is a deficient number, since it is larger than the sum of its proper divisors (1506769).

28628231 is a wasteful number, since it uses less digits than its factorization.

28628231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1506768.

The product of its digits is 9216, while the sum is 32.

The square root of 28628231 is about 5350.5355806685. The cubic root of 28628231 is about 305.9131675818.

The spelling of 28628231 in words is "twenty-eight million, six hundred twenty-eight thousand, two hundred thirty-one".