1686498491 has 2 divisors, whose sum is σ = 1686498492. Its totient is φ = 1686498490.

The previous prime is 1686498449. The next prime is 1686498493. The reversal of 1686498491 is 1948946861.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1686498491 - 2⁶ = 1686498427 is a prime.

Together with 1686498493, 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 (1686498493) 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, 843249245 + 843249246.

It is an arithmetic number, because the mean of its divisors is an integer number (843249246).

Almost surely, 2^1686498491 is an apocalyptic number.

1686498491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1686498491 is an equidigital number, since it uses as much as digits as its factorization.

1686498491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2985984, while the sum is 56.

The square root of 1686498491 is about 41067.0000243505. Note that the first 4 decimals coincide. The cubic root of 1686498491 is about 1190.3152169685.

The spelling of 1686498491 in words is "one billion, six hundred eighty-six million, four hundred ninety-eight thousand, four hundred ninety-one".