661606 has 32 divisors (see below), whose sum is σ = 1205280. Its totient is φ = 268800.

The previous prime is 661603. The next prime is 661607. The reversal of 661606 is 606166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661603) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10816 + ... + 10876.

It is an arithmetic number, because the mean of its divisors is an integer number (37665).

2⁶⁶¹⁶⁰⁶ is an apocalyptic number.

661606 is a deficient number, since it is larger than the sum of its proper divisors (543674).

661606 is a wasteful number, since it uses less digits than its factorization.

661606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 661606 is about 813.3916645749. The cubic root of 661606 is about 87.1364398085.

It can be divided in two parts, 66160 and 6, that added together give a palindrome (66166).

The spelling of 661606 in words is "six hundred sixty-one thousand, six hundred six".