1646661 has 12 divisors (see below), whose sum is σ = 2247648. Its totient is φ = 1072224.

The previous prime is 1646647. The next prime is 1646669. The reversal of 1646661 is 1666461.

It is not a de Polignac number, because 1646661 - 2⁵ = 1646629 is a prime.

It is a super-2 number, since 2×1646661² = 5422984897842, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1646669) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 15936 + ... + 16038.

It is an arithmetic number, because the mean of its divisors is an integer number (187304).

2^1646661 is an apocalyptic number.

It is an amenable number.

1646661 is a deficient number, since it is larger than the sum of its proper divisors (600987).

1646661 is an equidigital number, since it uses as much as digits as its factorization.

1646661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252 (or 179 counting only the distinct ones).

The product of its digits is 5184, while the sum is 30.

The square root of 1646661 is about 1283.2228956810. Note that the first 3 decimals coincide. The cubic root of 1646661 is about 118.0868124930.

The spelling of 1646661 in words is "one million, six hundred forty-six thousand, six hundred sixty-one".