21389376529 has 4 divisors (see below), whose sum is σ = 21446721076. Its totient is φ = 21332031984.

The previous prime is 21389376527. The next prime is 21389376581. The reversal of 21389376529 is 92567398312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17062368129 + 4327008400 = 130623^2 + 65780^2 .

It is a cyclic number.

It is not a de Polignac number, because 21389376529 - 2¹ = 21389376527 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 21389376529.

It is not an unprimeable number, because it can be changed into a prime (21389376527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28671714 + ... + 28672459.

It is an arithmetic number, because the mean of its divisors is an integer number (5361680269).

Almost surely, 2^21389376529 is an apocalyptic number.

It is an amenable number.

21389376529 is a deficient number, since it is larger than the sum of its proper divisors (57344547).

21389376529 is an equidigital number, since it uses as much as digits as its factorization.

21389376529 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57344546.

The product of its digits is 4898880, while the sum is 55.

The spelling of 21389376529 in words is "twenty-one billion, three hundred eighty-nine million, three hundred seventy-six thousand, five hundred twenty-nine".