201255556561 has 2 divisors, whose sum is σ = 201255556562. Its totient is φ = 201255556560.

The previous prime is 201255556553. The next prime is 201255556571. The reversal of 201255556561 is 165655552102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 193627280961 + 7628275600 = 440031^2 + 87340^2 .

It is a cyclic number.

It is not a de Polignac number, because 201255556561 - 2³ = 201255556553 is a prime.

It is not a weakly prime, because it can be changed into another prime (201255556511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100627778280 + 100627778281.

It is an arithmetic number, because the mean of its divisors is an integer number (100627778281).

Almost surely, 2^201255556561 is an apocalyptic number.

It is an amenable number.

201255556561 is a deficient number, since it is larger than the sum of its proper divisors (1).

201255556561 is an equidigital number, since it uses as much as digits as its factorization.

201255556561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 450000, while the sum is 43.

The spelling of 201255556561 in words is "two hundred one billion, two hundred fifty-five million, five hundred fifty-six thousand, five hundred sixty-one".