28018231 has 4 divisors (see below), whose sum is σ = 28032264. Its totient is φ = 28004200.

The previous prime is 28018187. The next prime is 28018247. The reversal of 28018231 is 13281082.

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-28018231 is a prime.

It is a super-2 number, since 2×28018231² = 1570042536738722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28018196 and 28018205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28013231) 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, 3400 + ... + 8221.

It is an arithmetic number, because the mean of its divisors is an integer number (7008066).

Almost surely, 2^28018231 is an apocalyptic number.

28018231 is a deficient number, since it is larger than the sum of its proper divisors (14033).

28018231 is a wasteful number, since it uses less digits than its factorization.

28018231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14032.

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 28018231 is about 5293.2250093870. The cubic root of 28018231 is about 303.7247877147.

The spelling of 28018231 in words is "twenty-eight million, eighteen thousand, two hundred thirty-one".