6721511387 has 2 divisors, whose sum is σ = 6721511388. Its totient is φ = 6721511386.

The previous prime is 6721511333. The next prime is 6721511389. The reversal of 6721511387 is 7831151276.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6721511387 - 2²⁴ = 6704734171 is a prime.

Together with 6721511389, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (6721511389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3360755693 + 3360755694.

It is an arithmetic number, because the mean of its divisors is an integer number (3360755694).

Almost surely, 2^6721511387 is an apocalyptic number.

6721511387 is a deficient number, since it is larger than the sum of its proper divisors (1).

6721511387 is an equidigital number, since it uses as much as digits as its factorization.

6721511387 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 70560, while the sum is 41.

The square root of 6721511387 is about 81984.8241261759. The cubic root of 6721511387 is about 1887.2190549613.

The spelling of 6721511387 in words is "six billion, seven hundred twenty-one million, five hundred eleven thousand, three hundred eighty-seven".