321400021 has 2 divisors, whose sum is σ = 321400022. Its totient is φ = 321400020.

The previous prime is 321399997. The next prime is 321400097. The reversal of 321400021 is 120004123.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 320052100 + 1347921 = 17890^2 + 1161^2 .

It is a cyclic number.

It is not a de Polignac number, because 321400021 - 2⁵ = 321399989 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 321399974 and 321400010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (321400421) 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, 160700010 + 160700011.

It is an arithmetic number, because the mean of its divisors is an integer number (160700011).

Almost surely, 2^321400021 is an apocalyptic number.

It is an amenable number.

321400021 is a deficient number, since it is larger than the sum of its proper divisors (1).

321400021 is an equidigital number, since it uses as much as digits as its factorization.

321400021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 321400021 is about 17927.6328889232. The cubic root of 321400021 is about 684.9864284167.

Adding to 321400021 its reverse (120004123), we get a palindrome (441404144).

The spelling of 321400021 in words is "three hundred twenty-one million, four hundred thousand, twenty-one".