6721643629 has 2 divisors, whose sum is σ = 6721643630. Its totient is φ = 6721643628.

The previous prime is 6721643611. The next prime is 6721643633. The reversal of 6721643629 is 9263461276.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6436371529 + 285272100 = 80227^2 + 16890^2 .

It is a cyclic number.

It is not a de Polignac number, because 6721643629 - 2⁷ = 6721643501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6721643609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3360821814 + 3360821815.

It is an arithmetic number, because the mean of its divisors is an integer number (3360821815).

Almost surely, 2^6721643629 is an apocalyptic number.

It is an amenable number.

6721643629 is a deficient number, since it is larger than the sum of its proper divisors (1).

6721643629 is an equidigital number, since it uses as much as digits as its factorization.

6721643629 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 653184, while the sum is 46.

The square root of 6721643629 is about 81985.6306251285. The cubic root of 6721643629 is about 1887.2314315420.

The spelling of 6721643629 in words is "six billion, seven hundred twenty-one million, six hundred forty-three thousand, six hundred twenty-nine".