1678681 has 4 divisors (see below), whose sum is σ = 1732864. Its totient is φ = 1624500.

The previous prime is 1678679. The next prime is 1678687. The reversal of 1678681 is 1868761.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1868761 = 619 ⋅3019.

It is a cyclic number.

It is not a de Polignac number, because 1678681 - 2¹ = 1678679 is a prime.

It is a super-2 number, since 2×1678681² = 5635939799522, which contains 22 as substring.

It is a Duffinian number.

1678681 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1678681.

It is not an unprimeable number, because it can be changed into a prime (1678687) 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, 27045 + ... + 27106.

It is an arithmetic number, because the mean of its divisors is an integer number (433216).

2^1678681 is an apocalyptic number.

It is an amenable number.

1678681 is a deficient number, since it is larger than the sum of its proper divisors (54183).

1678681 is an equidigital number, since it uses as much as digits as its factorization.

1678681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54182.

The product of its digits is 16128, while the sum is 37.

The square root of 1678681 is about 1295.6392244757. The cubic root of 1678681 is about 118.8473196674.

The spelling of 1678681 in words is "one million, six hundred seventy-eight thousand, six hundred eighty-one".