27991031 has 2 divisors, whose sum is σ = 27991032. Its totient is φ = 27991030.

The previous prime is 27991013. The next prime is 27991057. The reversal of 27991031 is 13019972.

It is a happy number.

Together with previous prime (27991013) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 27991031 - 2²² = 23796727 is a prime.

It is a super-2 number, since 2×27991031² = 1566995632885922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27991331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13995515 + 13995516.

It is an arithmetic number, because the mean of its divisors is an integer number (13995516).

Almost surely, 2^27991031 is an apocalyptic number.

27991031 is a deficient number, since it is larger than the sum of its proper divisors (1).

27991031 is an equidigital number, since it uses as much as digits as its factorization.

27991031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3402, while the sum is 32.

The square root of 27991031 is about 5290.6550634113. The cubic root of 27991031 is about 303.6264709078.

The spelling of 27991031 in words is "twenty-seven million, nine hundred ninety-one thousand, thirty-one".