661206 has 48 divisors (see below), whose sum is σ = 1666224. Its totient is φ = 173376.

The previous prime is 661201. The next prime is 661217. The reversal of 661206 is 602166.

661206 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 661206.

It is not an unprimeable number, because it can be changed into a prime (661201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3736 + ... + 3908.

It is an arithmetic number, because the mean of its divisors is an integer number (34713).

2⁶⁶¹²⁰⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661206, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (833112).

661206 is an abundant number, since it is smaller than the sum of its proper divisors (1005018).

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

661206 is a wasteful number, since it uses less digits than its factorization.

661206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205 (or 198 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 661206 is about 813.1457433941. The cubic root of 661206 is about 87.1188756779.

It can be divided in two parts, 6 and 61206, that multiplied together give a square (367236 = 606²).

The spelling of 661206 in words is "six hundred sixty-one thousand, two hundred six".