205123551415 has 4 divisors (see below), whose sum is σ = 246148261704. Its totient is φ = 164098841128.

The previous prime is 205123551383. The next prime is 205123551421. The reversal of 205123551415 is 514155321502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 514155321502 = 2 ⋅257077660751.

It is a cyclic number.

It is not a de Polignac number, because 205123551415 - 2⁵ = 205123551383 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 20512355137 + ... + 20512355146.

It is an arithmetic number, because the mean of its divisors is an integer number (61537065426).

Almost surely, 2^205123551415 is an apocalyptic number.

205123551415 is a deficient number, since it is larger than the sum of its proper divisors (41024710289).

205123551415 is an equidigital number, since it uses as much as digits as its factorization.

205123551415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41024710288.

The product of its (nonzero) digits is 30000, while the sum is 34.

Adding to 205123551415 its reverse (514155321502), we get a palindrome (719278872917).

The spelling of 205123551415 in words is "two hundred five billion, one hundred twenty-three million, five hundred fifty-one thousand, four hundred fifteen".