691698 has 32 divisors (see below), whose sum is σ = 1622016. Its totient is φ = 192528.

The previous prime is 691697. The next prime is 691709. The reversal of 691698 is 896196.

It is a super-2 number, since 2×691698² = 956892246408, which contains 22 as substring.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 691698.

It is not an unprimeable number, because it can be changed into a prime (691693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1615 + ... + 1997.

It is an arithmetic number, because the mean of its divisors is an integer number (50688).

2⁶⁹¹⁶⁹⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 691698, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (811008).

691698 is an abundant number, since it is smaller than the sum of its proper divisors (930318).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

691698 is a wasteful number, since it uses less digits than its factorization.

691698 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 438.

The product of its digits is 23328, while the sum is 39.

The square root of 691698 is about 831.6838341581. The cubic root of 691698 is about 88.4379852179.

The spelling of 691698 in words is "six hundred ninety-one thousand, six hundred ninety-eight".