6421157 has 2 divisors, whose sum is σ = 6421158. Its totient is φ = 6421156.

The previous prime is 6421141. The next prime is 6421159. The reversal of 6421157 is 7511246.

It is a Cunningham number, because it is equal to 2534²+1.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6421156 + 1 = 2534^2 + 1^2 .

It is a cyclic number.

It is not a de Polignac number, because 6421157 - 2⁴ = 6421141 is a prime.

Together with 6421159, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6421159) 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, 3210578 + 3210579.

It is an arithmetic number, because the mean of its divisors is an integer number (3210579).

Almost surely, 2^6421157 is an apocalyptic number.

It is an amenable number.

6421157 is a deficient number, since it is larger than the sum of its proper divisors (1).

6421157 is an equidigital number, since it uses as much as digits as its factorization.

6421157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1680, while the sum is 26.

The square root of 6421157 is about 2534.0001973165. Note that the first 3 decimals coincide. The cubic root of 6421157 is about 185.8679160147.

The spelling of 6421157 in words is "six million, four hundred twenty-one thousand, one hundred fifty-seven".