205423121505 has 32 divisors (see below), whose sum is σ = 376349174784. Its totient is φ = 93728131776.

The previous prime is 205423121489. The next prime is 205423121521. The reversal of 205423121505 is 505121324502.

It is an interprime number because it is at equal distance from previous prime (205423121489) and next prime (205423121521).

It is not a de Polignac number, because 205423121505 - 2⁴ = 205423121489 is a prime.

It is a Curzon 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 31 ways as a sum of consecutive naturals, for example, 1815459 + ... + 1925288.

It is an arithmetic number, because the mean of its divisors is an integer number (11760911712).

Almost surely, 2^205423121505 is an apocalyptic number.

It is an amenable number.

205423121505 is a deficient number, since it is larger than the sum of its proper divisors (170926053279).

205423121505 is a wasteful number, since it uses less digits than its factorization.

205423121505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3741285.

The product of its (nonzero) digits is 12000, while the sum is 30.

The spelling of 205423121505 in words is "two hundred five billion, four hundred twenty-three million, one hundred twenty-one thousand, five hundred five".