27985981 has 2 divisors, whose sum is σ = 27985982. Its totient is φ = 27985980.

The previous prime is 27985939. The next prime is 27986003. The reversal of 27985981 is 18958972.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27931225 + 54756 = 5285^2 + 234^2 .

It is a cyclic number.

It is not a de Polignac number, because 27985981 - 2⁹ = 27985469 is a prime.

It is a super-2 number, since 2×27985981² = 1566430265064722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27985921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13992990 + 13992991.

It is an arithmetic number, because the mean of its divisors is an integer number (13992991).

Almost surely, 2^27985981 is an apocalyptic number.

It is an amenable number.

27985981 is a deficient number, since it is larger than the sum of its proper divisors (1).

27985981 is an equidigital number, since it uses as much as digits as its factorization.

27985981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 362880, while the sum is 49.

The square root of 27985981 is about 5290.1777852923. The cubic root of 27985981 is about 303.6082102264.

The spelling of 27985981 in words is "twenty-seven million, nine hundred eighty-five thousand, nine hundred eighty-one".