6631421 has 2 divisors, whose sum is σ = 6631422. Its totient is φ = 6631420.

The previous prime is 6631409. The next prime is 6631447. The reversal of 6631421 is 1241366.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6446521 + 184900 = 2539^2 + 430^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6631421 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6631021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3315710 + 3315711.

It is an arithmetic number, because the mean of its divisors is an integer number (3315711).

Almost surely, 2^6631421 is an apocalyptic number.

It is an amenable number.

6631421 is a deficient number, since it is larger than the sum of its proper divisors (1).

6631421 is an equidigital number, since it uses as much as digits as its factorization.

6631421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 23.

The square root of 6631421 is about 2575.1545584683. The cubic root of 6631421 is about 187.8749451271.

Adding to 6631421 its reverse (1241366), we get a palindrome (7872787).

The spelling of 6631421 in words is "six million, six hundred thirty-one thousand, four hundred twenty-one".