19810201 has 2 divisors, whose sum is σ = 19810202. Its totient is φ = 19810200.

The previous prime is 19810163. The next prime is 19810211. The reversal of 19810201 is 10201891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18490000 + 1320201 = 4300^2 + 1149^2 .

It is a cyclic number.

It is not a de Polignac number, because 19810201 - 2⁷ = 19810073 is a prime.

It is equal to p_1259302 and since 19810201 and 1259302 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (19810211) 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, 9905100 + 9905101.

It is an arithmetic number, because the mean of its divisors is an integer number (9905101).

Almost surely, 2^19810201 is an apocalyptic number.

It is an amenable number.

19810201 is a deficient number, since it is larger than the sum of its proper divisors (1).

19810201 is an equidigital number, since it uses as much as digits as its factorization.

19810201 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 22.

The square root of 19810201 is about 4450.8651967904. The cubic root of 19810201 is about 270.5803747976.

The spelling of 19810201 in words is "nineteen million, eight hundred ten thousand, two hundred one".