28947231 has 6 divisors (see below), whose sum is σ = 41812680. Its totient is φ = 19298148.

The previous prime is 28947181. The next prime is 28947251. The reversal of 28947231 is 13274982.

It is not a de Polignac number, because 28947231 - 2⁷ = 28947103 is a prime.

It is a super-2 number, since 2×28947231² = 1675884365134722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28947251) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1608171 + ... + 1608188.

It is an arithmetic number, because the mean of its divisors is an integer number (6968780).

Almost surely, 2^28947231 is an apocalyptic number.

28947231 is a deficient number, since it is larger than the sum of its proper divisors (12865449).

28947231 is a wasteful number, since it uses less digits than its factorization.

28947231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3216365 (or 3216362 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 28947231 is about 5380.2630976561. The cubic root of 28947231 is about 307.0452210510.

The spelling of 28947231 in words is "twenty-eight million, nine hundred forty-seven thousand, two hundred thirty-one".