205423979 has 2 divisors, whose sum is σ = 205423980. Its totient is φ = 205423978.

The previous prime is 205423951. The next prime is 205423987. The reversal of 205423979 is 979324502.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205423979 is a prime.

It is a super-2 number, since 2×205423979² = 84398022296384882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (205423909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102711989 + 102711990.

It is an arithmetic number, because the mean of its divisors is an integer number (102711990).

Almost surely, 2^205423979 is an apocalyptic number.

205423979 is a deficient number, since it is larger than the sum of its proper divisors (1).

205423979 is an equidigital number, since it uses as much as digits as its factorization.

205423979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 136080, while the sum is 41.

The square root of 205423979 is about 14332.6194047006. The cubic root of 205423979 is about 590.0430678128.

The spelling of 205423979 in words is "two hundred five million, four hundred twenty-three thousand, nine hundred seventy-nine".