1685730491 has 2 divisors, whose sum is σ = 1685730492. Its totient is φ = 1685730490.

The previous prime is 1685730481. The next prime is 1685730499. The reversal of 1685730491 is 1940375861.

It is a strong prime.

It is an emirp because it is prime and its reverse (1940375861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1685730491 - 2¹⁸ = 1685468347 is a prime.

It is not a weakly prime, because it can be changed into another prime (1685730499) 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, 842865245 + 842865246.

It is an arithmetic number, because the mean of its divisors is an integer number (842865246).

Almost surely, 2^1685730491 is an apocalyptic number.

1685730491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1685730491 is an equidigital number, since it uses as much as digits as its factorization.

1685730491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 181440, while the sum is 44.

The square root of 1685730491 is about 41057.6483861412. The cubic root of 1685730491 is about 1190.1345070754.

The spelling of 1685730491 in words is "one billion, six hundred eighty-five million, seven hundred thirty thousand, four hundred ninety-one".