1681406 has 4 divisors (see below), whose sum is σ = 2522112. Its totient is φ = 840702.

The previous prime is 1681403. The next prime is 1681411. The reversal of 1681406 is 6041861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6041861 = 7 ⋅863123.

It is a super-2 number, since 2×1681406² = 5654252273672, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1681403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420350 + ... + 420353.

It is an arithmetic number, because the mean of its divisors is an integer number (630528).

2^1681406 is an apocalyptic number.

1681406 is a deficient number, since it is larger than the sum of its proper divisors (840706).

1681406 is an equidigital number, since it uses as much as digits as its factorization.

1681406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 840705.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 1681406 is about 1296.6904025248. The cubic root of 1681406 is about 118.9115931186.

The spelling of 1681406 in words is "one million, six hundred eighty-one thousand, four hundred six".