21340512005 has 4 divisors (see below), whose sum is σ = 25608614412. Its totient is φ = 17072409600.

The previous prime is 21340511989. The next prime is 21340512031. The reversal of 21340512005 is 50021504312.

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 2230767361 + 19109744644 = 47231^2 + 138238^2 .

It is not a de Polignac number, because 21340512005 - 2⁴ = 21340511989 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2134051196 + ... + 2134051205.

It is an arithmetic number, because the mean of its divisors is an integer number (6402153603).

Almost surely, 2^21340512005 is an apocalyptic number.

It is an amenable number.

21340512005 is a deficient number, since it is larger than the sum of its proper divisors (4268102407).

21340512005 is an equidigital number, since it uses as much as digits as its factorization.

21340512005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4268102406.

The product of its (nonzero) digits is 1200, while the sum is 23.

The spelling of 21340512005 in words is "twenty-one billion, three hundred forty million, five hundred twelve thousand, five".