28009831 has 2 divisors, whose sum is σ = 28009832. Its totient is φ = 28009830.

The previous prime is 28009823. The next prime is 28009889. The reversal of 28009831 is 13890082.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28009831 - 2³ = 28009823 is a prime.

It is a super-2 number, since 2×28009831² = 1569101265297122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28009793 and 28009802.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28009801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14004915 + 14004916.

It is an arithmetic number, because the mean of its divisors is an integer number (14004916).

Almost surely, 2^28009831 is an apocalyptic number.

28009831 is a deficient number, since it is larger than the sum of its proper divisors (1).

28009831 is an equidigital number, since it uses as much as digits as its factorization.

28009831 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 28009831 is about 5292.4314827875. The cubic root of 28009831 is about 303.6944319650.

The spelling of 28009831 in words is "twenty-eight million, nine thousand, eight hundred thirty-one".