11643721 has 2 divisors, whose sum is σ = 11643722. Its totient is φ = 11643720.

The previous prime is 11643701. The next prime is 11643743. The reversal of 11643721 is 12734611.

11643721 is digitally balanced in base 2, 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., 10653696 + 990025 = 3264^2 + 995^2 .

It is a cyclic number.

It is not a de Polignac number, because 11643721 - 2⁹ = 11643209 is a prime.

It is a nialpdrome in base 11.

It is a zygodrome in base 11.

It is not a weakly prime, because it can be changed into another prime (11643701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5821860 + 5821861.

It is an arithmetic number, because the mean of its divisors is an integer number (5821861).

Almost surely, 2^11643721 is an apocalyptic number.

It is an amenable number.

11643721 is a deficient number, since it is larger than the sum of its proper divisors (1).

11643721 is an equidigital number, since it uses as much as digits as its factorization.

11643721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008, while the sum is 25.

The square root of 11643721 is about 3412.2897004797. The cubic root of 11643721 is about 226.6542830124.

The spelling of 11643721 in words is "eleven million, six hundred forty-three thousand, seven hundred twenty-one".