1688694493 has 2 divisors, whose sum is σ = 1688694494. Its totient is φ = 1688694492.

The previous prime is 1688694479. The next prime is 1688694499. The reversal of 1688694493 is 3944968861.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1674691929 + 14002564 = 40923^2 + 3742^2 .

It is a cyclic number.

It is not a de Polignac number, because 1688694493 - 2²⁹ = 1151823581 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1688694499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 844347246 + 844347247.

It is an arithmetic number, because the mean of its divisors is an integer number (844347247).

Almost surely, 2^1688694493 is an apocalyptic number.

It is an amenable number.

1688694493 is a deficient number, since it is larger than the sum of its proper divisors (1).

1688694493 is an equidigital number, since it uses as much as digits as its factorization.

1688694493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8957952, while the sum is 58.

The square root of 1688694493 is about 41093.7281467623. The cubic root of 1688694493 is about 1190.8316322692.

The spelling of 1688694493 in words is "one billion, six hundred eighty-eight million, six hundred ninety-four thousand, four hundred ninety-three".