27031561 has 2 divisors, whose sum is σ = 27031562. Its totient is φ = 27031560.

The previous prime is 27031559. The next prime is 27031573. The reversal of 27031561 is 16513072.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14107536 + 12924025 = 3756^2 + 3595^2 .

It is a cyclic number.

It is not a de Polignac number, because 27031561 - 2¹ = 27031559 is a prime.

Together with 27031559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (27031591) 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, 13515780 + 13515781.

It is an arithmetic number, because the mean of its divisors is an integer number (13515781).

Almost surely, 2^27031561 is an apocalyptic number.

It is an amenable number.

27031561 is a deficient number, since it is larger than the sum of its proper divisors (1).

27031561 is an equidigital number, since it uses as much as digits as its factorization.

27031561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 27031561 is about 5199.1884943710. The cubic root of 27031561 is about 300.1168470759.

The spelling of 27031561 in words is "twenty-seven million, thirty-one thousand, five hundred sixty-one".