20716729 has 16 divisors (see below), whose sum is σ = 23250240. Its totient is φ = 18300160.

The previous prime is 20716697. The next prime is 20716739. The reversal of 20716729 is 92761702.

It is a cyclic number.

It is not a de Polignac number, because 20716729 - 2⁵ = 20716697 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20716694 and 20716703.

It is not an unprimeable number, because it can be changed into a prime (20716739) 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 in 15 ways as a sum of consecutive naturals, for example, 88797 + ... + 89029.

It is an arithmetic number, because the mean of its divisors is an integer number (1453140).

Almost surely, 2^20716729 is an apocalyptic number.

It is an amenable number.

20716729 is a deficient number, since it is larger than the sum of its proper divisors (2533511).

20716729 is a wasteful number, since it uses less digits than its factorization.

20716729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 440.

The product of its (nonzero) digits is 10584, while the sum is 34.

The square root of 20716729 is about 4551.5633577926. The cubic root of 20716729 is about 274.6462846269.

The spelling of 20716729 in words is "twenty million, seven hundred sixteen thousand, seven hundred twenty-nine".