1223681 has 4 divisors (see below), whose sum is σ = 1228500. Its totient is φ = 1218864.

The previous prime is 1223633. The next prime is 1223683. The reversal of 1223681 is 1863221.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 442225 + 781456 = 665^2 + 884^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1223681 is a prime.

It is a super-2 number, since 2×1223681² = 2994790379522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1223683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2006 + ... + 2543.

It is an arithmetic number, because the mean of its divisors is an integer number (307125).

2^1223681 is an apocalyptic number.

It is an amenable number.

1223681 is a deficient number, since it is larger than the sum of its proper divisors (4819).

1223681 is an equidigital number, since it uses as much as digits as its factorization.

1223681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4818.

The product of its digits is 576, while the sum is 23.

The square root of 1223681 is about 1106.2011571138. The cubic root of 1223681 is about 106.9603311769.

The spelling of 1223681 in words is "one million, two hundred twenty-three thousand, six hundred eighty-one".