1681644 has 24 divisors (see below), whose sum is σ = 4016320. Its totient is φ = 547344.

The previous prime is 1681639. The next prime is 1681649. The reversal of 1681644 is 4461861.

It is an interprime number because it is at equal distance from previous prime (1681639) and next prime (1681649).

It is not an unprimeable number, because it can be changed into a prime (1681649) 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 7 ways as a sum of consecutive naturals, for example, 1114 + ... + 2145.

2^1681644 is an apocalyptic number.

It is an amenable number.

1681644 is an abundant number, since it is smaller than the sum of its proper divisors (2334676).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1681644 is a wasteful number, since it uses less digits than its factorization.

1681644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3309 (or 3307 counting only the distinct ones).

The product of its digits is 4608, while the sum is 30.

The square root of 1681644 is about 1296.7821713765. The cubic root of 1681644 is about 118.9172034281.

The spelling of 1681644 in words is "one million, six hundred eighty-one thousand, six hundred forty-four".