205780819 has 2 divisors, whose sum is σ = 205780820. Its totient is φ = 205780818.

The previous prime is 205780789. The next prime is 205780823. The reversal of 205780819 is 918087502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 205780819 - 2²³ = 197392211 is a prime.

It is a super-2 number, since 2×205780819² = 84691490936621522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (205780879) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102890409 + 102890410.

It is an arithmetic number, because the mean of its divisors is an integer number (102890410).

Almost surely, 2^205780819 is an apocalyptic number.

205780819 is a deficient number, since it is larger than the sum of its proper divisors (1).

205780819 is an equidigital number, since it uses as much as digits as its factorization.

205780819 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 205780819 is about 14345.0625303621. The cubic root of 205780819 is about 590.3845228716.

The spelling of 205780819 in words is "two hundred five million, seven hundred eighty thousand, eight hundred nineteen".