401223821 has 2 divisors, whose sum is σ = 401223822. Its totient is φ = 401223820.

The previous prime is 401223803. The next prime is 401223829. The reversal of 401223821 is 128322104.

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., 386554921 + 14668900 = 19661^2 + 3830^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-401223821 is a prime.

It is a Sophie Germain 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 (401223829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200611910 + 200611911.

It is an arithmetic number, because the mean of its divisors is an integer number (200611911).

Almost surely, 2^401223821 is an apocalyptic number.

It is an amenable number.

401223821 is a deficient number, since it is larger than the sum of its proper divisors (1).

401223821 is an equidigital number, since it uses as much as digits as its factorization.

401223821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 401223821 is about 20030.5721585780. The cubic root of 401223821 is about 737.5569671977.

Adding to 401223821 its reverse (128322104), we get a palindrome (529545925).

The spelling of 401223821 in words is "four hundred one million, two hundred twenty-three thousand, eight hundred twenty-one".