21510466513 has 6 divisors (see below), whose sum is σ = 21836314626. Its totient is φ = 21189410352.

The previous prime is 21510466487. The next prime is 21510466517. The reversal of 21510466513 is 31566401512.

It can be written as a sum of positive squares in only one way, i.e., 20577041809 + 933424704 = 143447^2 + 30552^2 .

It is not a de Polignac number, because 21510466513 - 2⁹ = 21510466001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21510466517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2391420 + ... + 2400397.

It is an arithmetic number, because the mean of its divisors is an integer number (3639385771).

Almost surely, 2^21510466513 is an apocalyptic number.

It is an amenable number.

21510466513 is a deficient number, since it is larger than the sum of its proper divisors (325848113).

21510466513 is an frugal number, since it uses more digits than its factorization.

21510466513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4791951 (or 4791884 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 34.

The spelling of 21510466513 in words is "twenty-one billion, five hundred ten million, four hundred sixty-six thousand, five hundred thirteen".