1205661 has 4 divisors (see below), whose sum is σ = 1607552. Its totient is φ = 803772.

The previous prime is 1205653. The next prime is 1205663. The reversal of 1205661 is 1665021.

It is a happy number.

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 not a de Polignac number, because 1205661 - 2³ = 1205653 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1205663) 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, 200941 + ... + 200946.

It is an arithmetic number, because the mean of its divisors is an integer number (401888).

2^1205661 is an apocalyptic number.

It is an amenable number.

1205661 is a deficient number, since it is larger than the sum of its proper divisors (401891).

1205661 is an equidigital number, since it uses as much as digits as its factorization.

1205661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 401890.

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 1205661 is about 1098.0259559774. The cubic root of 1205661 is about 106.4326978952.

Adding to 1205661 its product of nonzero digits (360), we get a palindrome (1206021).

The spelling of 1205661 in words is "one million, two hundred five thousand, six hundred sixty-one".