205519939 has 2 divisors, whose sum is σ = 205519940. Its totient is φ = 205519938.

The previous prime is 205519907. The next prime is 205519969. The reversal of 205519939 is 939915502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 205519939 - 2⁵ = 205519907 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 205519895 and 205519904.

It is not a weakly prime, because it can be changed into another prime (205519969) 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, 102759969 + 102759970.

It is an arithmetic number, because the mean of its divisors is an integer number (102759970).

Almost surely, 2^205519939 is an apocalyptic number.

205519939 is a deficient number, since it is larger than the sum of its proper divisors (1).

205519939 is an equidigital number, since it uses as much as digits as its factorization.

205519939 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 109350, while the sum is 43.

The square root of 205519939 is about 14335.9666224500. The cubic root of 205519939 is about 590.1349294006.

The spelling of 205519939 in words is "two hundred five million, five hundred nineteen thousand, nine hundred thirty-nine".