221836729 has 2 divisors, whose sum is σ = 221836730. Its totient is φ = 221836728.

The previous prime is 221836717. The next prime is 221836733. The reversal of 221836729 is 927638122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 214681104 + 7155625 = 14652^2 + 2675^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221836729 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221836691 and 221836700.

It is not a weakly prime, because it can be changed into another prime (221836789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110918364 + 110918365.

It is an arithmetic number, because the mean of its divisors is an integer number (110918365).

Almost surely, 2^221836729 is an apocalyptic number.

It is an amenable number.

221836729 is a deficient number, since it is larger than the sum of its proper divisors (1).

221836729 is an equidigital number, since it uses as much as digits as its factorization.

221836729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 40.

The square root of 221836729 is about 14894.1844019738. The cubic root of 221836729 is about 605.3564177208.

The spelling of 221836729 in words is "two hundred twenty-one million, eight hundred thirty-six thousand, seven hundred twenty-nine".