28031931 has 12 divisors (see below), whose sum is σ = 40655160. Its totient is φ = 18612000.

The previous prime is 28031911. The next prime is 28031959. The reversal of 28031931 is 13913082.

It is not a de Polignac number, because 28031931 - 2⁷ = 28031803 is a prime.

It is a super-2 number, since 2×28031931² = 1571578311177522, which contains 22 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a plaindrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 28031895 and 28031904.

It is not an unprimeable number, because it can be changed into a prime (28031911) 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, 3946 + ... + 8463.

It is an arithmetic number, because the mean of its divisors is an integer number (3387930).

Almost surely, 2^28031931 is an apocalyptic number.

28031931 is a deficient number, since it is larger than the sum of its proper divisors (12623229).

28031931 is a wasteful number, since it uses less digits than its factorization.

28031931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12666 (or 12663 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 28031931 is about 5294.5189583191. The cubic root of 28031931 is about 303.7742834826.

The spelling of 28031931 in words is "twenty-eight million, thirty-one thousand, nine hundred thirty-one".