401243021 has 2 divisors, whose sum is σ = 401243022. Its totient is φ = 401243020.

The previous prime is 401242979. The next prime is 401243041. The reversal of 401243021 is 120342104.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 370562500 + 30680521 = 19250^2 + 5539^2 .

It is a cyclic number.

It is not a de Polignac number, because 401243021 - 2⁶ = 401242957 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (401243041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200621510 + 200621511.

It is an arithmetic number, because the mean of its divisors is an integer number (200621511).

Almost surely, 2^401243021 is an apocalyptic number.

It is an amenable number.

401243021 is a deficient number, since it is larger than the sum of its proper divisors (1).

401243021 is an equidigital number, since it uses as much as digits as its factorization.

401243021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 401243021 is about 20031.0514202325. The cubic root of 401243021 is about 737.5687319262.

Adding to 401243021 its reverse (120342104), we get a palindrome (521585125).

The spelling of 401243021 in words is "four hundred one million, two hundred forty-three thousand, twenty-one".