26999981 has 2 divisors, whose sum is σ = 26999982. Its totient is φ = 26999980.

The previous prime is 26999963. The next prime is 27000011. The reversal of 26999981 is 18999962.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26522500 + 477481 = 5150^2 + 691^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-26999981 is a prime.

It is a super-2 number, since 2×26999981² = 1457997948000722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (26939981) 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, 13499990 + 13499991.

It is an arithmetic number, because the mean of its divisors is an integer number (13499991).

Almost surely, 2^26999981 is an apocalyptic number.

It is an amenable number.

26999981 is a deficient number, since it is larger than the sum of its proper divisors (1).

26999981 is an equidigital number, since it uses as much as digits as its factorization.

26999981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 629856, while the sum is 53.

The square root of 26999981 is about 5196.1505944305. The cubic root of 26999981 is about 299.9999296296. Note that the first 4 decimals are identical.

The spelling of 26999981 in words is "twenty-six million, nine hundred ninety-nine thousand, nine hundred eighty-one".