1211661 has 12 divisors (see below), whose sum is σ = 1909440. Its totient is φ = 734280.

The previous prime is 1211659. The next prime is 1211669. The reversal of 1211661 is 1661121.

1211661 is a `hidden beast` number, since 1 + 2 + 1 + 1 + 661 = 666.

It is not a de Polignac number, because 1211661 - 2¹ = 1211659 is a prime.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211669) 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 11 ways as a sum of consecutive naturals, for example, 6021 + ... + 6218.

It is an arithmetic number, because the mean of its divisors is an integer number (159120).

2^1211661 is an apocalyptic number.

1211661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1211661 is a deficient number, since it is larger than the sum of its proper divisors (697779).

1211661 is a wasteful number, since it uses less digits than its factorization.

1211661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12256 (or 12253 counting only the distinct ones).

The product of its digits is 72, while the sum is 18.

The square root of 1211661 is about 1100.7547410754. The cubic root of 1211661 is about 106.6089607576.

Adding to 1211661 its reverse (1661121), we get a palindrome (2872782).

The spelling of 1211661 in words is "one million, two hundred eleven thousand, six hundred sixty-one".