630661 has 4 divisors (see below), whose sum is σ = 632332. Its totient is φ = 628992.

The previous prime is 630659. The next prime is 630677. The reversal of 630661 is 166036.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 624100 + 6561 = 790^2 + 81^2 .

It is a cyclic number.

It is not a de Polignac number, because 630661 - 2¹ = 630659 is a prime.

It is an Ulam number.

It is a Duffinian number.

630661 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (610661) 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 3 ways as a sum of consecutive naturals, for example, 31 + ... + 1123.

It is an arithmetic number, because the mean of its divisors is an integer number (158083).

2⁶³⁰⁶⁶¹ is an apocalyptic number.

It is an amenable number.

630661 is a deficient number, since it is larger than the sum of its proper divisors (1671).

630661 is a wasteful number, since it uses less digits than its factorization.

630661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1670.

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 630661 is about 794.1416750178. The cubic root of 630661 is about 85.7561598309.

Adding to 630661 its reverse (166036), we get a palindrome (796697).

The spelling of 630661 in words is "six hundred thirty thousand, six hundred sixty-one".