1223664561 has 24 divisors (see below), whose sum is σ = 2107847040. Its totient is φ = 668834496.

The previous prime is 1223664553. The next prime is 1223664593. The reversal of 1223664561 is 1654663221.

1223664561 is a `hidden beast` number, since 1 + 2 + 2 + 3 + 6 + 645 + 6 + 1 = 666.

It is not a de Polignac number, because 1223664561 - 2³ = 1223664553 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1223664521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 420796 + ... + 423693.

It is an arithmetic number, because the mean of its divisors is an integer number (87826960).

Almost surely, 2^1223664561 is an apocalyptic number.

It is an amenable number.

1223664561 is a deficient number, since it is larger than the sum of its proper divisors (884182479).

1223664561 is a wasteful number, since it uses less digits than its factorization.

1223664561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 844525 (or 844522 counting only the distinct ones).

The product of its digits is 51840, while the sum is 36.

The square root of 1223664561 is about 34980.9170977549. The cubic root of 1223664561 is about 1069.5985220434.

The spelling of 1223664561 in words is "one billion, two hundred twenty-three million, six hundred sixty-four thousand, five hundred sixty-one".