6623421 has 16 divisors (see below), whose sum is σ = 10687104. Its totient is φ = 3561984.

The previous prime is 6623417. The next prime is 6623423. The reversal of 6623421 is 1243266.

It is not a de Polignac number, because 6623421 - 2² = 6623417 is a prime.

It is a Curzon number.

6623421 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 6623391 and 6623400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6623423) 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 in 15 ways as a sum of consecutive naturals, for example, 8920 + ... + 9633.

It is an arithmetic number, because the mean of its divisors is an integer number (667944).

Almost surely, 2^6623421 is an apocalyptic number.

It is an amenable number.

6623421 is a deficient number, since it is larger than the sum of its proper divisors (4063683).

6623421 is a wasteful number, since it uses less digits than its factorization.

6623421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18580.

The product of its digits is 1728, while the sum is 24.

The square root of 6623421 is about 2573.6007848926. The cubic root of 6623421 is about 187.7993653300.

Adding to 6623421 its reverse (1243266), we get a palindrome (7866687).

The spelling of 6623421 in words is "six million, six hundred twenty-three thousand, four hundred twenty-one".