1224721 has 8 divisors (see below), whose sum is σ = 1308320. Its totient is φ = 1143072.

The previous prime is 1224709. The next prime is 1224739. The reversal of 1224721 is 1274221.

It is a happy number.

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

It is a 2-Lehmer number, since φ(1224721) divides (1224721-1)².

It is a cyclic number.

It is not a de Polignac number, because 1224721 - 2¹³ = 1216529 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1224701) 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 7 ways as a sum of consecutive naturals, for example, 946 + ... + 1828.

It is an arithmetic number, because the mean of its divisors is an integer number (163540).

2^1224721 is an apocalyptic number.

It is an amenable number.

1224721 is a deficient number, since it is larger than the sum of its proper divisors (83599).

1224721 is an equidigital number, since it uses as much as digits as its factorization.

1224721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 975.

The product of its digits is 224, while the sum is 19.

The square root of 1224721 is about 1106.6711345291. The cubic root of 1224721 is about 106.9906242695.

Adding to 1224721 its reverse (1274221), we get a palindrome (2498942).

The spelling of 1224721 in words is "one million, two hundred twenty-four thousand, seven hundred twenty-one".