1641985 has 4 divisors (see below), whose sum is σ = 1970388. Its totient is φ = 1313584.

The previous prime is 1641971. The next prime is 1642021. The reversal of 1641985 is 5891461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5891461 = 1559 ⋅3779.

It can be written as a sum of positive squares in 2 ways, for example, as 552049 + 1089936 = 743^2 + 1044^2 .

It is a cyclic number.

It is not a de Polignac number, because 1641985 - 2⁵ = 1641953 is a prime.

It is a super-2 number, since 2×1641985² = 5392229480450, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 1641985.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 164194 + ... + 164203.

It is an arithmetic number, because the mean of its divisors is an integer number (492597).

2^1641985 is an apocalyptic number.

It is an amenable number.

1641985 is a deficient number, since it is larger than the sum of its proper divisors (328403).

1641985 is an equidigital number, since it uses as much as digits as its factorization.

1641985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328402.

The product of its digits is 8640, while the sum is 34.

The square root of 1641985 is about 1281.3996254097. The cubic root of 1641985 is about 117.9749300375.

The spelling of 1641985 in words is "one million, six hundred forty-one thousand, nine hundred eighty-five".