1682021 has 6 divisors (see below), whose sum is σ = 1848966. Its totient is φ = 1529000.

The previous prime is 1682017. The next prime is 1682047. The reversal of 1682021 is 1202861.

1682021 = 126² + 127² + ... + 191².

It can be written as a sum of positive squares in only one way, i.e., 1600225 + 81796 = 1265^2 + 286^2 .

It is not a de Polignac number, because 1682021 - 2² = 1682017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 1681984 and 1682002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1682081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6830 + ... + 7071.

It is an arithmetic number, because the mean of its divisors is an integer number (308161).

2^1682021 is an apocalyptic number.

1682021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1682021 is a deficient number, since it is larger than the sum of its proper divisors (166945).

1682021 is a wasteful number, since it uses less digits than its factorization.

1682021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13923 (or 13912 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 1682021 is about 1296.9275230328. The cubic root of 1682021 is about 118.9260892636.

Adding to 1682021 its reverse (1202861), we get a palindrome (2884882).

It can be divided in two parts, 16820 and 21, that multiplied together give a triangular number (353220 = T₈₄₀).

The spelling of 1682021 in words is "one million, six hundred eighty-two thousand, twenty-one".