20983729 has 8 divisors (see below), whose sum is σ = 23927400. Its totient is φ = 18230016.

The previous prime is 20983727. The next prime is 20983741. The reversal of 20983729 is 92738902.

It can be written as a sum of positive squares in 4 ways, for example, as 490000 + 20493729 = 700^2 + 4527^2 .

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 20983729 - 2¹ = 20983727 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20983691 and 20983700.

It is not an unprimeable number, because it can be changed into a prime (20983723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47254 + ... + 47695.

It is an arithmetic number, because the mean of its divisors is an integer number (2990925).

Almost surely, 2^20983729 is an apocalyptic number.

It is an amenable number.

20983729 is a deficient number, since it is larger than the sum of its proper divisors (2943671).

20983729 is a wasteful number, since it uses less digits than its factorization.

20983729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94979.

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 20983729 is about 4580.8000392944. The cubic root of 20983729 is about 275.8211445363.

It can be divided in two parts, 20983 and 729, that added together give a palindrome (21712).

The spelling of 20983729 in words is "twenty million, nine hundred eighty-three thousand, seven hundred twenty-nine".