28381831 has 2 divisors, whose sum is σ = 28381832. Its totient is φ = 28381830.

The previous prime is 28381819. The next prime is 28381841. The reversal of 28381831 is 13818382.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28381831 - 2⁹ = 28381319 is a prime.

It is a super-2 number, since 2×28381831² = 1611056661825122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28381811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14190915 + 14190916.

It is an arithmetic number, because the mean of its divisors is an integer number (14190916).

Almost surely, 2^28381831 is an apocalyptic number.

28381831 is a deficient number, since it is larger than the sum of its proper divisors (1).

28381831 is an equidigital number, since it uses as much as digits as its factorization.

28381831 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9216, while the sum is 34.

The square root of 28381831 is about 5327.4600890105. The cubic root of 28381831 is about 305.0329839810.

The spelling of 28381831 in words is "twenty-eight million, three hundred eighty-one thousand, eight hundred thirty-one".