55111391 has 2 divisors, whose sum is σ = 55111392. Its totient is φ = 55111390.

The previous prime is 55111379. The next prime is 55111417. The reversal of 55111391 is 19311155.

It is an a-pointer prime, because the next prime (55111417) can be obtained adding 55111391 to its sum of digits (26).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 55111391 - 2⁶ = 55111327 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 55111391.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55111321) 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, 27555695 + 27555696.

It is an arithmetic number, because the mean of its divisors is an integer number (27555696).

Almost surely, 2^55111391 is an apocalyptic number.

55111391 is a deficient number, since it is larger than the sum of its proper divisors (1).

55111391 is an equidigital number, since it uses as much as digits as its factorization.

55111391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 675, while the sum is 26.

The square root of 55111391 is about 7423.7046681559. The cubic root of 55111391 is about 380.5518091173.

The spelling of 55111391 in words is "fifty-five million, one hundred eleven thousand, three hundred ninety-one".