205106217517 has 4 divisors (see below), whose sum is σ = 205569211680. Its totient is φ = 204643223356.

The previous prime is 205106217499. The next prime is 205106217521. The reversal of 205106217517 is 715712601502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 205106217517 - 2¹⁹ = 205105693229 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205106217587) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 231496417 + ... + 231497302.

It is an arithmetic number, because the mean of its divisors is an integer number (51392302920).

Almost surely, 2^205106217517 is an apocalyptic number.

It is an amenable number.

205106217517 is a deficient number, since it is larger than the sum of its proper divisors (462994163).

205106217517 is an equidigital number, since it uses as much as digits as its factorization.

205106217517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 462994162.

The product of its (nonzero) digits is 29400, while the sum is 37.

The spelling of 205106217517 in words is "two hundred five billion, one hundred six million, two hundred seventeen thousand, five hundred seventeen".