201838991 has 2 divisors, whose sum is σ = 201838992. Its totient is φ = 201838990.

The previous prime is 201838979. The next prime is 201838993. The reversal of 201838991 is 199838102.

201838991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 201838991 - 2¹⁸ = 201576847 is a prime.

Together with 201838993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201838993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100919495 + 100919496.

It is an arithmetic number, because the mean of its divisors is an integer number (100919496).

Almost surely, 2^201838991 is an apocalyptic number.

201838991 is a deficient number, since it is larger than the sum of its proper divisors (1).

201838991 is an equidigital number, since it uses as much as digits as its factorization.

201838991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 41.

The square root of 201838991 is about 14207.0049975355. The cubic root of 201838991 is about 586.5904959145.

The spelling of 201838991 in words is "two hundred one million, eight hundred thirty-eight thousand, nine hundred ninety-one".