1201661 has 4 divisors (see below), whose sum is σ = 1205472. Its totient is φ = 1197852.

The previous prime is 1201643. The next prime is 1201687. The reversal of 1201661 is 1661021.

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 a cyclic number.

It is not a de Polignac number, because 1201661 - 2¹⁰ = 1200637 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1201601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1385 + ... + 2078.

It is an arithmetic number, because the mean of its divisors is an integer number (301368).

2^1201661 is an apocalyptic number.

It is an amenable number.

1201661 is a deficient number, since it is larger than the sum of its proper divisors (3811).

1201661 is an equidigital number, since it uses as much as digits as its factorization.

1201661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3810.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 1201661 is about 1096.2029921506. The cubic root of 1201661 is about 106.3148641994.

Adding to 1201661 its reverse (1661021), we get a palindrome (2862682).

The spelling of 1201661 in words is "one million, two hundred one thousand, six hundred sixty-one".