1855820201 has 2 divisors, whose sum is σ = 1855820202. Its totient is φ = 1855820200.

The previous prime is 1855820191. The next prime is 1855820207. The reversal of 1855820201 is 1020285581.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1652016025 + 203804176 = 40645^2 + 14276^2 .

It is a cyclic number.

It is not a de Polignac number, because 1855820201 - 2¹⁰ = 1855819177 is a prime.

It is not a weakly prime, because it can be changed into another prime (1855820207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 927910100 + 927910101.

It is an arithmetic number, because the mean of its divisors is an integer number (927910101).

Almost surely, 2^1855820201 is an apocalyptic number.

It is an amenable number.

1855820201 is a deficient number, since it is larger than the sum of its proper divisors (1).

1855820201 is an equidigital number, since it uses as much as digits as its factorization.

1855820201 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6400, while the sum is 32.

The square root of 1855820201 is about 43079.2316667788. The cubic root of 1855820201 is about 1228.8870451212.

The spelling of 1855820201 in words is "one billion, eight hundred fifty-five million, eight hundred twenty thousand, two hundred one".