21112729 has 16 divisors (see below), whose sum is σ = 23821056. Its totient is φ = 18547200.

The previous prime is 21112727. The next prime is 21112733. The reversal of 21112729 is 92721112.

It is a cyclic number.

It is not a de Polignac number, because 21112729 - 2¹ = 21112727 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21112723) 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 15 ways as a sum of consecutive naturals, for example, 49939 + ... + 50359.

It is an arithmetic number, because the mean of its divisors is an integer number (1488816).

Almost surely, 2^21112729 is an apocalyptic number.

It is an amenable number.

21112729 is a deficient number, since it is larger than the sum of its proper divisors (2708327).

21112729 is a wasteful number, since it uses less digits than its factorization.

21112729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 576.

The product of its digits is 504, while the sum is 25.

The square root of 21112729 is about 4594.8589749850. The cubic root of 21112729 is about 276.3852047974.

The spelling of 21112729 in words is "twenty-one million, one hundred twelve thousand, seven hundred twenty-nine".