6390421 has 4 divisors (see below), whose sum is σ = 6495244. Its totient is φ = 6285600.

The previous prime is 6390413. The next prime is 6390427. The reversal of 6390421 is 1240936.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 509796 + 5880625 = 714^2 + 2425^2 .

It is a cyclic number.

It is not a de Polignac number, because 6390421 - 2³ = 6390413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6390427) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52320 + ... + 52441.

It is an arithmetic number, because the mean of its divisors is an integer number (1623811).

Almost surely, 2^6390421 is an apocalyptic number.

6390421 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

6390421 is the 1460-th hex number.

It is an amenable number.

6390421 is a deficient number, since it is larger than the sum of its proper divisors (104823).

6390421 is a wasteful number, since it uses less digits than its factorization.

6390421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104822.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 6390421 is about 2527.9282030944. The cubic root of 6390421 is about 185.5708783858.

The spelling of 6390421 in words is "six million, three hundred ninety thousand, four hundred twenty-one".