555551111 has 2 divisors, whose sum is σ = 555551112. Its totient is φ = 555551110.

The previous prime is 555551077. The next prime is 555551137. The reversal of 555551111 is 111155555.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 555551111 - 2¹⁰ = 555550087 is a prime.

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (555551911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 277775555 + 277775556.

It is an arithmetic number, because the mean of its divisors is an integer number (277775556).

Almost surely, 2^555551111 is an apocalyptic number.

555551111 is a deficient number, since it is larger than the sum of its proper divisors (1).

555551111 is an equidigital number, since it uses as much as digits as its factorization.

555551111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3125, while the sum is 29.

The square root of 555551111 is about 23570.1317561018. The cubic root of 555551111 is about 822.0684991943.

It can be divided in two parts, 55555 and 1111, that multiplied together give a triangular number (61721605 = T₁₁₁₁₀).

The spelling of 555551111 in words is "five hundred fifty-five million, five hundred fifty-one thousand, one hundred eleven".