201019991 has 2 divisors, whose sum is σ = 201019992. Its totient is φ = 201019990.

The previous prime is 201019961. The next prime is 201019999. The reversal of 201019991 is 199910102.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 201019991 - 2¹⁰ = 201018967 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201019999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100509995 + 100509996.

It is an arithmetic number, because the mean of its divisors is an integer number (100509996).

Almost surely, 2^201019991 is an apocalyptic number.

201019991 is a deficient number, since it is larger than the sum of its proper divisors (1).

201019991 is an equidigital number, since it uses as much as digits as its factorization.

201019991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1458, while the sum is 32.

The square root of 201019991 is about 14178.1518894389. The cubic root of 201019991 is about 585.7960196213.

The spelling of 201019991 in words is "two hundred one million, nineteen thousand, nine hundred ninety-one".