21392128889 has 4 divisors (see below), whose sum is σ = 21422646180. Its totient is φ = 21361611600.

The previous prime is 21392128873. The next prime is 21392128907. The reversal of 21392128889 is 98882129312.

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 9978411664 + 11413717225 = 99892^2 + 106835^2 .

It is a cyclic number.

It is not a de Polignac number, because 21392128889 - 2⁴ = 21392128873 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 21392128889.

It is not an unprimeable number, because it can be changed into a prime (21592128889) 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, 15257594 + ... + 15258995.

It is an arithmetic number, because the mean of its divisors is an integer number (5355661545).

Almost surely, 2^21392128889 is an apocalyptic number.

It is an amenable number.

21392128889 is a deficient number, since it is larger than the sum of its proper divisors (30517291).

21392128889 is an equidigital number, since it uses as much as digits as its factorization.

21392128889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30517290.

The product of its digits is 995328, while the sum is 53.

The spelling of 21392128889 in words is "twenty-one billion, three hundred ninety-two million, one hundred twenty-eight thousand, eight hundred eighty-nine".