201000000991 has 2 divisors, whose sum is σ = 201000000992. Its totient is φ = 201000000990.

The previous prime is 201000000989. The next prime is 201000001001. The reversal of 201000000991 is 199000000102.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 201000000991 - 2¹ = 201000000989 is a prime.

Together with 201000000989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201000000941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100500000495 + 100500000496.

It is an arithmetic number, because the mean of its divisors is an integer number (100500000496).

Almost surely, 2^201000000991 is an apocalyptic number.

201000000991 is a deficient number, since it is larger than the sum of its proper divisors (1).

201000000991 is an equidigital number, since it uses as much as digits as its factorization.

201000000991 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 201000000991 in words is "two hundred one billion, nine hundred ninety-one", and thus it is an aban number.