6420405 has 8 divisors (see below), whose sum is σ = 10272672. Its totient is φ = 3424208.

The previous prime is 6420391. The next prime is 6420413. The reversal of 6420405 is 5040246.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6420405 - 2⁴ = 6420389 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 213999 + ... + 214028.

It is an arithmetic number, because the mean of its divisors is an integer number (1284084).

Almost surely, 2^6420405 is an apocalyptic number.

It is an amenable number.

6420405 is a deficient number, since it is larger than the sum of its proper divisors (3852267).

6420405 is a wasteful number, since it uses less digits than its factorization.

6420405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 428035.

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 6420405 is about 2533.8518109787. The cubic root of 6420405 is about 185.8606598910.

The spelling of 6420405 in words is "six million, four hundred twenty thousand, four hundred five".