26809681 has 2 divisors, whose sum is σ = 26809682. Its totient is φ = 26809680.

The previous prime is 26809661. The next prime is 26809687. The reversal of 26809681 is 18690862.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22648081 + 4161600 = 4759^2 + 2040^2 .

It is a cyclic number.

It is not a de Polignac number, because 26809681 - 2⁵ = 26809649 is a prime.

It is a super-2 number, since 2×26809681² = 1437517990643522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (26809687) 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, 13404840 + 13404841.

It is an arithmetic number, because the mean of its divisors is an integer number (13404841).

Almost surely, 2^26809681 is an apocalyptic number.

It is an amenable number.

26809681 is a deficient number, since it is larger than the sum of its proper divisors (1).

26809681 is an equidigital number, since it uses as much as digits as its factorization.

26809681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 41472, while the sum is 40.

The square root of 26809681 is about 5177.8065819418. The cubic root of 26809681 is about 299.2934520880.

The spelling of 26809681 in words is "twenty-six million, eight hundred nine thousand, six hundred eighty-one".