6404621 has 8 divisors (see below), whose sum is σ = 6658200. Its totient is φ = 6153280.

The previous prime is 6404611. The next prime is 6404623. The reversal of 6404621 is 1264046.

6404621 = 1789² + 1790².

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3721 + 6400900 = 61^2 + 2530^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6404621 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 (6404623) 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 7 ways as a sum of consecutive naturals, for example, 7391 + ... + 8211.

It is an arithmetic number, because the mean of its divisors is an integer number (832275).

Almost surely, 2^6404621 is an apocalyptic number.

6404621 is the 1790-th centered square number.

It is an amenable number.

6404621 is a deficient number, since it is larger than the sum of its proper divisors (253579).

6404621 is a wasteful number, since it uses less digits than its factorization.

6404621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1119.

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 6404621 is about 2530.7352686522. The cubic root of 6404621 is about 185.7082275567.

Adding to 6404621 its reverse (1264046), we get a palindrome (7668667).

The spelling of 6404621 in words is "six million, four hundred four thousand, six hundred twenty-one".