6686157421 has 2 divisors, whose sum is σ = 6686157422. Its totient is φ = 6686157420.

The previous prime is 6686157383. The next prime is 6686157461. The reversal of 6686157421 is 1247516866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6614568900 + 71588521 = 81330^2 + 8461^2 .

It is a cyclic number.

It is not a de Polignac number, because 6686157421 - 2⁹ = 6686156909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6686157461) 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, 3343078710 + 3343078711.

It is an arithmetic number, because the mean of its divisors is an integer number (3343078711).

Almost surely, 2^6686157421 is an apocalyptic number.

It is an amenable number.

6686157421 is a deficient number, since it is larger than the sum of its proper divisors (1).

6686157421 is an equidigital number, since it uses as much as digits as its factorization.

6686157421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 483840, while the sum is 46.

The square root of 6686157421 is about 81768.9269894133. The cubic root of 6686157421 is about 1883.9044234169.

The spelling of 6686157421 in words is "six billion, six hundred eighty-six million, one hundred fifty-seven thousand, four hundred twenty-one".