28205931 has 12 divisors (see below), whose sum is σ = 40724088. Its totient is φ = 17357184.

The previous prime is 28205921. The next prime is 28205963. The reversal of 28205931 is 13950282.

It is a happy number.

It is not a de Polignac number, because 28205931 - 2¹¹ = 28203883 is a prime.

It is a super-2 number, since 2×28205931² = 1591149087153522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28205921) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27310 + ... + 28323.

It is an arithmetic number, because the mean of its divisors is an integer number (3393674).

Almost surely, 2^28205931 is an apocalyptic number.

28205931 is a deficient number, since it is larger than the sum of its proper divisors (12518157).

28205931 is a wasteful number, since it uses less digits than its factorization.

28205931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55662 (or 55649 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 28205931 is about 5310.9256255384. The cubic root of 28205931 is about 304.4015174358.

The spelling of 28205931 in words is "twenty-eight million, two hundred five thousand, nine hundred thirty-one".