205878562643961 has 9 divisors (see below), whose sum is σ = 297380208217989. Its totient is φ = 137252346399036.

The previous prime is 205878562643927. The next prime is 205878562643981. The reversal of 205878562643961 is 169346265878502.

The square root of 205878562643961 is 14348469.

It is a perfect power (a square), and thus also a powerful number.

205878562643961 is a `hidden beast` number, since 2 + 0 + 5 + 8 + 78 + 5 + 62 + 6 + 439 + 61 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is a de Polignac number, because none of the positive numbers 2^k-205878562643961 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 205878562643961.

It is not an unprimeable number, because it can be changed into a prime (205878562643981) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 40653996 + ... + 45436818.

It is a 1-persistent number, because it is pandigital, but 2⋅205878562643961 = 411757125287922 is not.

Almost surely, 2^{205878562643961} is an apocalyptic number.

205878562643961 is the 14348469-th square number.

205878562643961 is the 7174235-th centered octagonal number.

It is an amenable number.

205878562643961 is a deficient number, since it is larger than the sum of its proper divisors (91501645574028).

205878562643961 is an frugal number, since it uses more digits than its factorization.

205878562643961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9565652 (or 4782826 counting only the distinct ones).

The product of its (nonzero) digits is 1045094400, while the sum is 72.

The spelling of 205878562643961 in words is "two hundred five trillion, eight hundred seventy-eight billion, five hundred sixty-two million, six hundred forty-three thousand, nine hundred sixty-one".