1207721 has 2 divisors, whose sum is σ = 1207722. Its totient is φ = 1207720.

The previous prime is 1207699. The next prime is 1207727. The reversal of 1207721 is 1277021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1132096 + 75625 = 1064^2 + 275^2 .

It is an emirp because it is prime and its reverse (1277021) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1207721 - 2¹⁸ = 945577 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1207693 and 1207702.

It is not a weakly prime, because it can be changed into another prime (1207727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 603860 + 603861.

It is an arithmetic number, because the mean of its divisors is an integer number (603861).

2^1207721 is an apocalyptic number.

It is an amenable number.

1207721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1207721 is an equidigital number, since it uses as much as digits as its factorization.

1207721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 196, while the sum is 20.

The square root of 1207721 is about 1098.9636026730. The cubic root of 1207721 is about 106.4932805976.

The spelling of 1207721 in words is "one million, two hundred seven thousand, seven hundred twenty-one".