1681893 has 6 divisors (see below), whose sum is σ = 2429414. Its totient is φ = 1121256.

The previous prime is 1681891. The next prime is 1681903. The reversal of 1681893 is 3981861.

It can be written as a sum of positive squares in only one way, i.e., 1520289 + 161604 = 1233^2 + 402^2 .

It is not a de Polignac number, because 1681893 - 2¹ = 1681891 is a prime.

It is a Duffinian number.

1681893 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1681891) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 93430 + ... + 93447.

2^1681893 is an apocalyptic number.

It is an amenable number.

1681893 is a deficient number, since it is larger than the sum of its proper divisors (747521).

1681893 is a wasteful number, since it uses less digits than its factorization.

1681893 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 186883 (or 186880 counting only the distinct ones).

The product of its digits is 10368, while the sum is 36.

The square root of 1681893 is about 1296.8781746949. The cubic root of 1681893 is about 118.9230724710.

Subtracting 1681893 from its reverse (3981861), we obtain a cube (2299968 = 132³).

The spelling of 1681893 in words is "one million, six hundred eighty-one thousand, eight hundred ninety-three".