20529438721 has 4 divisors (see below), whose sum is σ = 22395751344. Its totient is φ = 18663126100.

The previous prime is 20529438679. The next prime is 20529438773. The reversal of 20529438721 is 12783492502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20529438721 - 2¹⁷ = 20529307649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20529438521) 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 3 ways as a sum of consecutive naturals, for example, 933156295 + ... + 933156316.

It is an arithmetic number, because the mean of its divisors is an integer number (5598937836).

Almost surely, 2^20529438721 is an apocalyptic number.

It is an amenable number.

20529438721 is a deficient number, since it is larger than the sum of its proper divisors (1866312623).

20529438721 is a wasteful number, since it uses less digits than its factorization.

20529438721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1866312622.

The product of its (nonzero) digits is 241920, while the sum is 43.

The spelling of 20529438721 in words is "twenty billion, five hundred twenty-nine million, four hundred thirty-eight thousand, seven hundred twenty-one".