673661 has 6 divisors (see below), whose sum is σ = 697086. Its totient is φ = 651000.

The previous prime is 673649. The next prime is 673667. The reversal of 673661 is 166376.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 649636 + 24025 = 806^2 + 155^2 .

It is a de Polignac number, because none of the positive numbers 2^k-673661 is a prime.

It is a Duffinian number.

It is a plaindrome in base 6.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (673667) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 611 + ... + 1311.

It is an arithmetic number, because the mean of its divisors is an integer number (116181).

2⁶⁷³⁶⁶¹ is an apocalyptic number.

It is an amenable number.

673661 is a deficient number, since it is larger than the sum of its proper divisors (23425).

673661 is an equidigital number, since it uses as much as digits as its factorization.

673661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 763 (or 732 counting only the distinct ones).

The product of its digits is 4536, while the sum is 29.

The square root of 673661 is about 820.7685422822. The cubic root of 673661 is about 87.6624899017.

The spelling of 673661 in words is "six hundred seventy-three thousand, six hundred sixty-one".