1691943 has 24 divisors (see below), whose sum is σ = 2553600. Its totient is φ = 995280.

The previous prime is 1691939. The next prime is 1691983. The reversal of 1691943 is 3491961.

It is not a de Polignac number, because 1691943 - 2² = 1691939 is a prime.

It is a super-2 number, since 2×1691943² = 5725342230498, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1691933) 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, 21378 + ... + 21456.

It is an arithmetic number, because the mean of its divisors is an integer number (106400).

2^1691943 is an apocalyptic number.

1691943 is a deficient number, since it is larger than the sum of its proper divisors (861657).

1691943 is a wasteful number, since it uses less digits than its factorization.

1691943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163 (or 152 counting only the distinct ones).

The product of its digits is 5832, while the sum is 33.

The square root of 1691943 is about 1300.7470930200. The cubic root of 1691943 is about 119.1594735961.

It can be divided in two parts, 169 and 1943, that added together give a palindrome (2112).

The spelling of 1691943 in words is "one million, six hundred ninety-one thousand, nine hundred forty-three".