21064729 has 8 divisors (see below), whose sum is σ = 24724928. Its totient is φ = 17567280.

The previous prime is 21064723. The next prime is 21064753. The reversal of 21064729 is 92746012.

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 21064729 - 2¹¹ = 21062681 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21064729.

It is not an unprimeable number, because it can be changed into a prime (21064723) 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, 40407 + ... + 40924.

It is an arithmetic number, because the mean of its divisors is an integer number (3090616).

Almost surely, 2^21064729 is an apocalyptic number.

It is an amenable number.

21064729 is a deficient number, since it is larger than the sum of its proper divisors (3660199).

21064729 is an equidigital number, since it uses as much as digits as its factorization.

21064729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81375.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 21064729 is about 4589.6327739809. The cubic root of 21064729 is about 276.1755910239.

The spelling of 21064729 in words is "twenty-one million, sixty-four thousand, seven hundred twenty-nine".