28131871 has 2 divisors, whose sum is σ = 28131872. Its totient is φ = 28131870.

The previous prime is 28131853. The next prime is 28131881. The reversal of 28131871 is 17813182.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28131871 - 2¹³ = 28123679 is a prime.

It is equal to p_1749118 and since 28131871 and 1749118 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28131811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14065935 + 14065936.

It is an arithmetic number, because the mean of its divisors is an integer number (14065936).

Almost surely, 2^28131871 is an apocalyptic number.

28131871 is a deficient number, since it is larger than the sum of its proper divisors (1).

28131871 is an equidigital number, since it uses as much as digits as its factorization.

28131871 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 31.

The square root of 28131871 is about 5303.9486234314. The cubic root of 28131871 is about 304.1348626866.

The spelling of 28131871 in words is "twenty-eight million, one hundred thirty-one thousand, eight hundred seventy-one".