28951231 has 4 divisors (see below), whose sum is σ = 30475000. Its totient is φ = 27427464.

The previous prime is 28951229. The next prime is 28951243. The reversal of 28951231 is 13215982.

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

It is a cyclic number.

It is not a de Polignac number, because 28951231 - 2¹ = 28951229 is a prime.

It is a super-2 number, since 2×28951231² = 1676347552830722, 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 = 28951193 and 28951202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28951211) 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, 761856 + ... + 761893.

It is an arithmetic number, because the mean of its divisors is an integer number (7618750).

Almost surely, 2^28951231 is an apocalyptic number.

28951231 is a deficient number, since it is larger than the sum of its proper divisors (1523769).

28951231 is a wasteful number, since it uses less digits than its factorization.

28951231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1523768.

The product of its digits is 4320, while the sum is 31.

The square root of 28951231 is about 5380.6348138486. The cubic root of 28951231 is about 307.0593631558.

The spelling of 28951231 in words is "twenty-eight million, nine hundred fifty-one thousand, two hundred thirty-one".