11640721 has 2 divisors, whose sum is σ = 11640722. Its totient is φ = 11640720.

The previous prime is 11640719. The next prime is 11640731. The reversal of 11640721 is 12704611.

11640721 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7230721 + 4410000 = 2689^2 + 2100^2 .

It is a cyclic number.

It is not a de Polignac number, because 11640721 - 2¹ = 11640719 is a prime.

Together with 11640719, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 11640692 and 11640701.

It is not a weakly prime, because it can be changed into another prime (11640731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5820360 + 5820361.

It is an arithmetic number, because the mean of its divisors is an integer number (5820361).

Almost surely, 2^11640721 is an apocalyptic number.

It is an amenable number.

11640721 is a deficient number, since it is larger than the sum of its proper divisors (1).

11640721 is an equidigital number, since it uses as much as digits as its factorization.

11640721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 11640721 is about 3411.8500846315. The cubic root of 11640721 is about 226.6348155456.

The spelling of 11640721 in words is "eleven million, six hundred forty thousand, seven hundred twenty-one".