201999971 has 2 divisors, whose sum is σ = 201999972. Its totient is φ = 201999970.

The previous prime is 201999929. The next prime is 201999991. The reversal of 201999971 is 179999102.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 201999971 - 2²² = 197805667 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (201999991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100999985 + 100999986.

It is an arithmetic number, because the mean of its divisors is an integer number (100999986).

Almost surely, 2^201999971 is an apocalyptic number.

201999971 is a deficient number, since it is larger than the sum of its proper divisors (1).

201999971 is an equidigital number, since it uses as much as digits as its factorization.

201999971 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 91854, while the sum is 47.

The square root of 201999971 is about 14212.6693833354. The cubic root of 201999971 is about 586.7464027656.

It can be divided in two parts, 20 and 1999971, that added together give a palindrome (1999991).

The spelling of 201999971 in words is "two hundred one million, nine hundred ninety-nine thousand, nine hundred seventy-one".