205660561557 has 8 divisors (see below), whose sum is σ = 299142635040. Its totient is φ = 124642764560.

The previous prime is 205660561507. The next prime is 205660561571. The reversal of 205660561557 is 755165066502.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 205660561557 - 2⁶ = 205660561493 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205660561507) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3116069082 + ... + 3116069147.

It is an arithmetic number, because the mean of its divisors is an integer number (37392829380).

Almost surely, 2^205660561557 is an apocalyptic number.

It is an amenable number.

205660561557 is a deficient number, since it is larger than the sum of its proper divisors (93482073483).

205660561557 is a wasteful number, since it uses less digits than its factorization.

205660561557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6232138243.

The product of its (nonzero) digits is 1890000, while the sum is 48.

The spelling of 205660561557 in words is "two hundred five billion, six hundred sixty million, five hundred sixty-one thousand, five hundred fifty-seven".