390421 has 2 divisors, whose sum is σ = 390422. Its totient is φ = 390420.

The previous prime is 390419. The next prime is 390433. The reversal of 390421 is 124093.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 260100 + 130321 = 510^2 + 361^2 .

It is a cyclic number.

It is not a de Polignac number, because 390421 - 2¹ = 390419 is a prime.

Together with 390419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (390491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195210 + 195211.

It is an arithmetic number, because the mean of its divisors is an integer number (195211).

2³⁹⁰⁴²¹ is an apocalyptic number.

It is an amenable number.

390421 is a deficient number, since it is larger than the sum of its proper divisors (1).

390421 is an equidigital number, since it uses as much as digits as its factorization.

390421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 390421 is about 624.8367786870. The cubic root of 390421 is about 73.0877159143.

The spelling of 390421 in words is "three hundred ninety thousand, four hundred twenty-one".