1691745686 has 4 divisors (see below), whose sum is σ = 2537618532. Its totient is φ = 845872842.

The previous prime is 1691745673. The next prime is 1691745691. The reversal of 1691745686 is 6865471961.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×1691745686² = 5724006932199221192, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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, 422936420 + ... + 422936423.

It is an arithmetic number, because the mean of its divisors is an integer number (634404633).

Almost surely, 2^1691745686 is an apocalyptic number.

1691745686 is a deficient number, since it is larger than the sum of its proper divisors (845872846).

1691745686 is an equidigital number, since it uses as much as digits as its factorization.

1691745686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 845872845.

The product of its digits is 2177280, while the sum is 53.

The square root of 1691745686 is about 41130.8361937853. The cubic root of 1691745686 is about 1191.5484129927.

The spelling of 1691745686 in words is "one billion, six hundred ninety-one million, seven hundred forty-five thousand, six hundred eighty-six".