691641 has 24 divisors (see below), whose sum is σ = 1074944. Its totient is φ = 427680.

The previous prime is 691637. The next prime is 691651. The reversal of 691641 is 146196.

It is not a de Polignac number, because 691641 - 2² = 691637 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 691641.

It is not an unprimeable number, because it can be changed into a prime (691631) 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 23 ways as a sum of consecutive naturals, for example, 10290 + ... + 10356.

2⁶⁹¹⁶⁴¹ is an apocalyptic number.

It is an amenable number.

691641 is a deficient number, since it is larger than the sum of its proper divisors (383303).

691641 is a wasteful number, since it uses less digits than its factorization.

691641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141 (or 138 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 691641 is about 831.6495656224. The cubic root of 691641 is about 88.4355558805.

The spelling of 691641 in words is "six hundred ninety-one thousand, six hundred forty-one".