26668991 has 2 divisors, whose sum is σ = 26668992. Its totient is φ = 26668990.

The previous prime is 26668981. The next prime is 26668997. The reversal of 26668991 is 19986662.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 26668991 - 2⁶ = 26668927 is a prime.

It is a super-2 number, since 2×26668991² = 1422470161916162, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (26668997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13334495 + 13334496.

It is an arithmetic number, because the mean of its divisors is an integer number (13334496).

Almost surely, 2^26668991 is an apocalyptic number.

26668991 is a deficient number, since it is larger than the sum of its proper divisors (1).

26668991 is an equidigital number, since it uses as much as digits as its factorization.

26668991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 279936, while the sum is 47.

The square root of 26668991 is about 5164.2028426467. The cubic root of 26668991 is about 298.7689964170.

The spelling of 26668991 in words is "twenty-six million, six hundred sixty-eight thousand, nine hundred ninety-one".