205666254515 has 4 divisors (see below), whose sum is σ = 246799505424. Its totient is φ = 164533003608.

The previous prime is 205666254511. The next prime is 205666254527. The reversal of 205666254515 is 515452666502.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 205666254515 - 2² = 205666254511 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 205666254515.

It is not an unprimeable number, because it can be changed into a prime (205666254511) 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, 20566625447 + ... + 20566625456.

It is an arithmetic number, because the mean of its divisors is an integer number (61699876356).

Almost surely, 2^205666254515 is an apocalyptic number.

205666254515 is a deficient number, since it is larger than the sum of its proper divisors (41133250909).

205666254515 is an equidigital number, since it uses as much as digits as its factorization.

205666254515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41133250908.

The product of its (nonzero) digits is 2160000, while the sum is 47.

The spelling of 205666254515 in words is "two hundred five billion, six hundred sixty-six million, two hundred fifty-four thousand, five hundred fifteen".