633661 has 4 divisors (see below), whose sum is σ = 724192. Its totient is φ = 543132.

The previous prime is 633653. The next prime is 633667. The reversal of 633661 is 166336.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 633661 - 2³ = 633653 is a prime.

633661 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (633667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45255 + ... + 45268.

It is an arithmetic number, because the mean of its divisors is an integer number (181048).

2⁶³³⁶⁶¹ is an apocalyptic number.

It is an amenable number.

633661 is a deficient number, since it is larger than the sum of its proper divisors (90531).

633661 is an equidigital number, since it uses as much as digits as its factorization.

633661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90530.

The product of its digits is 1944, while the sum is 25.

The square root of 633661 is about 796.0282658298. The cubic root of 633661 is about 85.8919230060.

Adding to 633661 its reverse (166336), we get a palindrome (799997).

The spelling of 633661 in words is "six hundred thirty-three thousand, six hundred sixty-one".