27631561 has 2 divisors, whose sum is σ = 27631562. Its totient is φ = 27631560.

The previous prime is 27631559. The next prime is 27631589. The reversal of 27631561 is 16513672.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27248400 + 383161 = 5220^2 + 619^2 .

It is a cyclic number.

It is not a de Polignac number, because 27631561 - 2¹ = 27631559 is a prime.

Together with 27631559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (27631061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13815780 + 13815781.

It is an arithmetic number, because the mean of its divisors is an integer number (13815781).

Almost surely, 2^27631561 is an apocalyptic number.

It is an amenable number.

27631561 is a deficient number, since it is larger than the sum of its proper divisors (1).

27631561 is an equidigital number, since it uses as much as digits as its factorization.

27631561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7560, while the sum is 31.

The square root of 27631561 is about 5256.5731232429. The cubic root of 27631561 is about 302.3211099943.

The spelling of 27631561 in words is "twenty-seven million, six hundred thirty-one thousand, five hundred sixty-one".