204554511266661 has 6 divisors (see below), whose sum is σ = 295467627385190. Its totient is φ = 136369674177768.

The previous prime is 204554511266641. The next prime is 204554511266669. The reversal of 204554511266661 is 166662115455402.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 203621198768100 + 933312498561 = 14269590^2 + 966081^2 .

It is not a de Polignac number, because 204554511266661 - 2²¹ = 204554509169509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 204554511266598 and 204554511266607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204554511266669) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11364139514806 + ... + 11364139514823.

Almost surely, 2^{204554511266661} is an apocalyptic number.

It is an amenable number.

204554511266661 is a deficient number, since it is larger than the sum of its proper divisors (90913116118529).

204554511266661 is a wasteful number, since it uses less digits than its factorization.

204554511266661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22728279029635 (or 22728279029632 counting only the distinct ones).

The product of its (nonzero) digits is 10368000, while the sum is 54.

The spelling of 204554511266661 in words is "two hundred four trillion, five hundred fifty-four billion, five hundred eleven million, two hundred sixty-six thousand, six hundred sixty-one".