1223210721 has 8 divisors (see below), whose sum is σ = 1631626624. Its totient is φ = 815134320.

The previous prime is 1223210717. The next prime is 1223210731. The reversal of 1223210721 is 1270123221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1223210721 - 2² = 1223210717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1223210731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76345 + ... + 90966.

It is an arithmetic number, because the mean of its divisors is an integer number (203953328).

Almost surely, 2^1223210721 is an apocalyptic number.

It is an amenable number.

1223210721 is a deficient number, since it is larger than the sum of its proper divisors (408415903).

1223210721 is a wasteful number, since it uses less digits than its factorization.

1223210721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169751.

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 1223210721 is about 34974.4295307300. The cubic root of 1223210721 is about 1069.4662726689.

Adding to 1223210721 its reverse (1270123221), we get a palindrome (2493333942).

The spelling of 1223210721 in words is "one billion, two hundred twenty-three million, two hundred ten thousand, seven hundred twenty-one".