1681931 has 2 divisors, whose sum is σ = 1681932. Its totient is φ = 1681930.

The previous prime is 1681907. The next prime is 1681957. The reversal of 1681931 is 1391861.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (1391861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1681931 - 2¹⁰ = 1680907 is a prime.

It is a super-2 number, since 2×1681931² = 5657783777522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1681894 and 1681903.

It is not a weakly prime, because it can be changed into another prime (1681991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 840965 + 840966.

It is an arithmetic number, because the mean of its divisors is an integer number (840966).

2^1681931 is an apocalyptic number.

1681931 is a deficient number, since it is larger than the sum of its proper divisors (1).

1681931 is an equidigital number, since it uses as much as digits as its factorization.

1681931 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1296, while the sum is 29.

The square root of 1681931 is about 1296.8928251787. The cubic root of 1681931 is about 118.9239680973.

The spelling of 1681931 in words is "one million, six hundred eighty-one thousand, nine hundred thirty-one".