6721157 has 2 divisors, whose sum is σ = 6721158. Its totient is φ = 6721156.

The previous prime is 6721153. The next prime is 6721159. The reversal of 6721157 is 7511276.

6721157 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5354596 + 1366561 = 2314^2 + 1169^2 .

It is a cyclic number.

It is not a de Polignac number, because 6721157 - 2² = 6721153 is a prime.

Together with 6721159, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6721153) 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 as a sum of consecutive naturals, namely, 3360578 + 3360579.

It is an arithmetic number, because the mean of its divisors is an integer number (3360579).

Almost surely, 2^6721157 is an apocalyptic number.

It is an amenable number.

6721157 is a deficient number, since it is larger than the sum of its proper divisors (1).

6721157 is an equidigital number, since it uses as much as digits as its factorization.

6721157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2940, while the sum is 29.

The square root of 6721157 is about 2592.5194309783. The cubic root of 6721157 is about 188.7185886942.

The spelling of 6721157 in words is "six million, seven hundred twenty-one thousand, one hundred fifty-seven".