55355561 has 2 divisors, whose sum is σ = 55355562. Its totient is φ = 55355560.

The previous prime is 55355551. The next prime is 55355563. The reversal of 55355561 is 16555355.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52649536 + 2706025 = 7256^2 + 1645^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55355561 is a prime.

Together with 55355563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (55355563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27677780 + 27677781.

It is an arithmetic number, because the mean of its divisors is an integer number (27677781).

Almost surely, 2^55355561 is an apocalyptic number.

It is an amenable number.

55355561 is a deficient number, since it is larger than the sum of its proper divisors (1).

55355561 is an equidigital number, since it uses as much as digits as its factorization.

55355561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56250, while the sum is 35.

The square root of 55355561 is about 7440.1317864672. The cubic root of 55355561 is about 381.1129904177.

The spelling of 55355561 in words is "fifty-five million, three hundred fifty-five thousand, five hundred sixty-one".