26991551 has 2 divisors, whose sum is σ = 26991552. Its totient is φ = 26991550.

The previous prime is 26991541. The next prime is 26991557. The reversal of 26991551 is 15519962.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-26991551 is a 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 (26991557) 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, 13495775 + 13495776.

It is an arithmetic number, because the mean of its divisors is an integer number (13495776).

Almost surely, 2^26991551 is an apocalyptic number.

26991551 is a deficient number, since it is larger than the sum of its proper divisors (1).

26991551 is an equidigital number, since it uses as much as digits as its factorization.

26991551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24300, while the sum is 38.

The square root of 26991551 is about 5195.3393536900. The cubic root of 26991551 is about 299.9687041428.

The spelling of 26991551 in words is "twenty-six million, nine hundred ninety-one thousand, five hundred fifty-one".