1219721 has 2 divisors, whose sum is σ = 1219722. Its totient is φ = 1219720.

The previous prime is 1219717. The next prime is 1219727. The reversal of 1219721 is 1279121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 846400 + 373321 = 920^2 + 611^2 .

It is a cyclic number.

It is not a de Polignac number, because 1219721 - 2² = 1219717 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1219727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 609860 + 609861.

It is an arithmetic number, because the mean of its divisors is an integer number (609861).

2^1219721 is an apocalyptic number.

It is an amenable number.

1219721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1219721 is an equidigital number, since it uses as much as digits as its factorization.

1219721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 252, while the sum is 23.

The square root of 1219721 is about 1104.4097971315. The cubic root of 1219721 is about 106.8448270443.

The spelling of 1219721 in words is "one million, two hundred nineteen thousand, seven hundred twenty-one".