991000000201 has 2 divisors, whose sum is σ = 991000000202. Its totient is φ = 991000000200.

The previous prime is 991000000181. The next prime is 991000000217. The reversal of 991000000201 is 102000000199.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 976339633801 + 14660366400 = 988099^2 + 121080^2 .

It is a cyclic number.

It is not a de Polignac number, because 991000000201 - 2⁷ = 991000000073 is a prime.

It is not a weakly prime, because it can be changed into another prime (991000000241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495500000100 + 495500000101.

It is an arithmetic number, because the mean of its divisors is an integer number (495500000101).

Almost surely, 2^991000000201 is an apocalyptic number.

It is an amenable number.

991000000201 is a deficient number, since it is larger than the sum of its proper divisors (1).

991000000201 is an equidigital number, since it uses as much as digits as its factorization.

991000000201 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162, while the sum is 22.

The spelling of 991000000201 in words is "nine hundred ninety-one billion, two hundred one", and thus it is an aban number.