21064303505 has 12 divisors (see below), whose sum is σ = 29404048500. Its totient is φ = 14444093664.

The previous prime is 21064303499. The next prime is 21064303571. The reversal of 21064303505 is 50530346012.

It can be written as a sum of positive squares in 2 ways, for example, as 2968942144 + 18095361361 = 54488^2 + 134519^2 .

It is not a de Polignac number, because 21064303505 - 2²⁶ = 20997194641 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42988130 + ... + 42988619.

It is an arithmetic number, because the mean of its divisors is an integer number (2450337375).

Almost surely, 2^21064303505 is an apocalyptic number.

It is an amenable number.

21064303505 is a deficient number, since it is larger than the sum of its proper divisors (8339744995).

21064303505 is an equidigital number, since it uses as much as digits as its factorization.

21064303505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85976768 (or 85976761 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 29.

Adding to 21064303505 its reverse (50530346012), we get a palindrome (71594649517).

The spelling of 21064303505 in words is "twenty-one billion, sixty-four million, three hundred three thousand, five hundred five".