28091831 has 2 divisors, whose sum is σ = 28091832. Its totient is φ = 28091830.

The previous prime is 28091813. The next prime is 28091863. The reversal of 28091831 is 13819082.

Together with previous prime (28091813) it forms an Ormiston pair, because they use the same digits, order apart.

It is an a-pointer prime, because the next prime (28091863) can be obtained adding 28091831 to its sum of digits (32).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28091831 - 2²² = 23897527 is a prime.

It is a super-2 number, since 2×28091831² = 1578301937865122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28091801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14045915 + 14045916.

It is an arithmetic number, because the mean of its divisors is an integer number (14045916).

Almost surely, 2^28091831 is an apocalyptic number.

28091831 is a deficient number, since it is larger than the sum of its proper divisors (1).

28091831 is an equidigital number, since it uses as much as digits as its factorization.

28091831 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 32.

The square root of 28091831 is about 5300.1727330343. The cubic root of 28091831 is about 303.9905027908.

The spelling of 28091831 in words is "twenty-eight million, ninety-one thousand, eight hundred thirty-one".