21312010205 has 8 divisors (see below), whose sum is σ = 25666740312. Its totient is φ = 16988056128.

The previous prime is 21312010201. The next prime is 21312010219. The reversal of 21312010205 is 50201021312.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 710862244 + 20601147961 = 26662^2 + 143531^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21312010205 - 2² = 21312010201 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312010201) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 7692482 + ... + 7695251.

It is an arithmetic number, because the mean of its divisors is an integer number (3208342539).

Almost surely, 2^21312010205 is an apocalyptic number.

It is an amenable number.

21312010205 is a deficient number, since it is larger than the sum of its proper divisors (4354730107).

21312010205 is a wasteful number, since it uses less digits than its factorization.

21312010205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15388015.

The product of its (nonzero) digits is 120, while the sum is 17.

Adding to 21312010205 its reverse (50201021312), we get a palindrome (71513031517).

The spelling of 21312010205 in words is "twenty-one billion, three hundred twelve million, ten thousand, two hundred five".