691943 has 4 divisors (see below), whose sum is σ = 790800. Its totient is φ = 593088.

The previous prime is 691931. The next prime is 691949. The reversal of 691943 is 349196.

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

It is a cyclic number.

It is not a de Polignac number, because 691943 - 2⁸ = 691687 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 691943.

It is not an unprimeable number, because it can be changed into a prime (691949) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49418 + ... + 49431.

It is an arithmetic number, because the mean of its divisors is an integer number (197700).

2⁶⁹¹⁹⁴³ is an apocalyptic number.

691943 is a deficient number, since it is larger than the sum of its proper divisors (98857).

691943 is an equidigital number, since it uses as much as digits as its factorization.

691943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98856.

The product of its digits is 5832, while the sum is 32.

The square root of 691943 is about 831.8311126665. The cubic root of 691943 is about 88.4484255877.

The spelling of 691943 in words is "six hundred ninety-one thousand, nine hundred forty-three".