1681919 has 4 divisors (see below), whose sum is σ = 1705680. Its totient is φ = 1658160.

The previous prime is 1681907. The next prime is 1681931. The reversal of 1681919 is 9191861.

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

It is an interprime number because it is at equal distance from previous prime (1681907) and next prime (1681931).

It is a cyclic number.

It is not a de Polignac number, because 1681919 - 2⁴ = 1681903 is a prime.

It is a super-2 number, since 2×1681919² = 5657703045122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1681219) 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, 11774 + ... + 11915.

It is an arithmetic number, because the mean of its divisors is an integer number (426420).

2^1681919 is an apocalyptic number.

1681919 is a deficient number, since it is larger than the sum of its proper divisors (23761).

1681919 is an equidigital number, since it uses as much as digits as its factorization.

1681919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23760.

The product of its digits is 3888, while the sum is 35.

The square root of 1681919 is about 1296.8881987280. Note that the first 3 decimals coincide. The cubic root of 1681919 is about 118.9236852694.

The spelling of 1681919 in words is "one million, six hundred eighty-one thousand, nine hundred nineteen".