205321945257 has 48 divisors (see below), whose sum is σ = 359322696000. Its totient is φ = 114865395840.

The previous prime is 205321945229. The next prime is 205321945273. The reversal of 205321945257 is 752549123502.

205321945257 is a `hidden beast` number, since 2 + 0 + 5 + 32 + 1 + 94 + 525 + 7 = 666.

It is not a de Polignac number, because 205321945257 - 2¹¹ = 205321943209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (205321945957) 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 in 47 ways as a sum of consecutive naturals, for example, 1995132 + ... + 2095517.

It is an arithmetic number, because the mean of its divisors is an integer number (7485889500).

Almost surely, 2^205321945257 is an apocalyptic number.

205321945257 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

205321945257 is a deficient number, since it is larger than the sum of its proper divisors (154000750743).

205321945257 is a wasteful number, since it uses less digits than its factorization.

205321945257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4090695 (or 4090676 counting only the distinct ones).

The product of its (nonzero) digits is 756000, while the sum is 45.

The spelling of 205321945257 in words is "two hundred five billion, three hundred twenty-one million, nine hundred forty-five thousand, two hundred fifty-seven".