55511557 has 2 divisors, whose sum is σ = 55511558. Its totient is φ = 55511556.

The previous prime is 55511543. The next prime is 55511569. The reversal of 55511557 is 75511555.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 35450116 + 20061441 = 5954^2 + 4479^2 .

It is a cyclic number.

It is not a de Polignac number, because 55511557 - 2⁷ = 55511429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55511537) 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, 27755778 + 27755779.

It is an arithmetic number, because the mean of its divisors is an integer number (27755779).

Almost surely, 2^55511557 is an apocalyptic number.

It is an amenable number.

55511557 is a deficient number, since it is larger than the sum of its proper divisors (1).

55511557 is an equidigital number, since it uses as much as digits as its factorization.

55511557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21875, while the sum is 34.

The square root of 55511557 is about 7450.6078275534. The cubic root of 55511557 is about 381.4706560341.

The spelling of 55511557 in words is "fifty-five million, five hundred eleven thousand, five hundred fifty-seven".