205101608661 has 24 divisors (see below), whose sum is σ = 298248030080. Its totient is φ = 135816479136.

The previous prime is 205101608641. The next prime is 205101608711. The reversal of 205101608661 is 166806101502.

205101608661 is a `hidden beast` number, since 2 + 0 + 510 + 1 + 6 + 0 + 86 + 61 = 666.

It is not a de Polignac number, because 205101608661 - 2⁶ = 205101608597 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 (205101608641) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4327056 + ... + 4374198.

Almost surely, 2^205101608661 is an apocalyptic number.

It is an amenable number.

205101608661 is a deficient number, since it is larger than the sum of its proper divisors (93146421419).

205101608661 is a wasteful number, since it uses less digits than its factorization.

205101608661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50385 (or 50382 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The spelling of 205101608661 in words is "two hundred five billion, one hundred one million, six hundred eight thousand, six hundred sixty-one".