21128430005 has 8 divisors (see below), whose sum is σ = 25769757624. Its totient is φ = 16625649600.

The previous prime is 21128429983. The next prime is 21128430007. The reversal of 21128430005 is 50003482112.

It can be written as a sum of positive squares in 4 ways, for example, as 218980804 + 20909449201 = 14798^2 + 144601^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21128430005 - 2⁶ = 21128429941 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21128430007) 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, 34636466 + ... + 34637075.

It is an arithmetic number, because the mean of its divisors is an integer number (3221219703).

Almost surely, 2^21128430005 is an apocalyptic number.

It is an amenable number.

21128430005 is a deficient number, since it is larger than the sum of its proper divisors (4641327619).

21128430005 is an equidigital number, since it uses as much as digits as its factorization.

21128430005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69273607.

The product of its (nonzero) digits is 1920, while the sum is 26.

The spelling of 21128430005 in words is "twenty-one billion, one hundred twenty-eight million, four hundred thirty thousand, five".