1230721 has 4 divisors (see below), whose sum is σ = 1232944. Its totient is φ = 1228500.

The previous prime is 1230689. The next prime is 1230727. The reversal of 1230721 is 1270321.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1230721 - 2⁵ = 1230689 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

1230721 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1230695 and 1230704.

It is not an unprimeable number, because it can be changed into a prime (1230727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 466 + ... + 1636.

It is an arithmetic number, because the mean of its divisors is an integer number (308236).

2^1230721 is an apocalyptic number.

1230721 is the 641-st hex number.

It is an amenable number.

1230721 is a deficient number, since it is larger than the sum of its proper divisors (2223).

1230721 is a wasteful number, since it uses less digits than its factorization.

1230721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2222.

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 1230721 is about 1109.3786549236. The cubic root of 1230721 is about 107.1650580873.

The spelling of 1230721 in words is "one million, two hundred thirty thousand, seven hundred twenty-one".