201698921 has 2 divisors, whose sum is σ = 201698922. Its totient is φ = 201698920.

The previous prime is 201698899. The next prime is 201698923. The reversal of 201698921 is 129896102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 194881600 + 6817321 = 13960^2 + 2611^2 .

It is a cyclic number.

It is not a de Polignac number, because 201698921 - 2¹⁰ = 201697897 is a prime.

Together with 201698923, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (201698923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100849460 + 100849461.

It is an arithmetic number, because the mean of its divisors is an integer number (100849461).

Almost surely, 2^201698921 is an apocalyptic number.

It is an amenable number.

201698921 is a deficient number, since it is larger than the sum of its proper divisors (1).

201698921 is an equidigital number, since it uses as much as digits as its factorization.

201698921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 201698921 is about 14202.0745315605. The cubic root of 201698921 is about 586.4547726431.

The spelling of 201698921 in words is "two hundred one million, six hundred ninety-eight thousand, nine hundred twenty-one".