204751191661 has 2 divisors, whose sum is σ = 204751191662. Its totient is φ = 204751191660.

The previous prime is 204751191653. The next prime is 204751191677. The reversal of 204751191661 is 166191157402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 109451797225 + 95299394436 = 330835^2 + 308706^2 .

It is a cyclic number.

It is not a de Polignac number, because 204751191661 - 2³ = 204751191653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (204751191611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102375595830 + 102375595831.

It is an arithmetic number, because the mean of its divisors is an integer number (102375595831).

Almost surely, 2^204751191661 is an apocalyptic number.

It is an amenable number.

204751191661 is a deficient number, since it is larger than the sum of its proper divisors (1).

204751191661 is an equidigital number, since it uses as much as digits as its factorization.

204751191661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90720, while the sum is 43.

The spelling of 204751191661 in words is "two hundred four billion, seven hundred fifty-one million, one hundred ninety-one thousand, six hundred sixty-one".