20956729 has 8 divisors (see below), whose sum is σ = 21346560. Its totient is φ = 20569296.

The previous prime is 20956709. The next prime is 20956739. The reversal of 20956729 is 92765902.

20956729 = T₂₂ + T₂₃ + ... + T₅₀₀.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20956729 - 2⁵ = 20956697 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20956691 and 20956700.

It is not an unprimeable number, because it can be changed into a prime (20956709) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31767 + ... + 32419.

It is an arithmetic number, because the mean of its divisors is an integer number (2668320).

Almost surely, 2^20956729 is an apocalyptic number.

It is an amenable number.

20956729 is a deficient number, since it is larger than the sum of its proper divisors (389831).

20956729 is an equidigital number, since it uses as much as digits as its factorization.

20956729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1199.

The product of its (nonzero) digits is 68040, while the sum is 40.

The square root of 20956729 is about 4577.8520072191. The cubic root of 20956729 is about 275.7027930379.

The spelling of 20956729 in words is "twenty million, nine hundred fifty-six thousand, seven hundred twenty-nine".