194021021 has 2 divisors, whose sum is σ = 194021022. Its totient is φ = 194021020.

The previous prime is 194020999. The next prime is 194021039. The reversal of 194021021 is 120120491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 128572921 + 65448100 = 11339^2 + 8090^2 .

It is an emirp because it is prime and its reverse (120120491) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 194021021 - 2¹⁴ = 194004637 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 194020984 and 194021002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (194021921) 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, 97010510 + 97010511.

It is an arithmetic number, because the mean of its divisors is an integer number (97010511).

Almost surely, 2^194021021 is an apocalyptic number.

It is an amenable number.

194021021 is a deficient number, since it is larger than the sum of its proper divisors (1).

194021021 is an equidigital number, since it uses as much as digits as its factorization.

194021021 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 20.

The square root of 194021021 is about 13929.1428666663. The cubic root of 194021021 is about 578.9169453404.

The spelling of 194021021 in words is "one hundred ninety-four million, twenty-one thousand, twenty-one".