21650064013 has 6 divisors (see below), whose sum is σ = 22632298094. Its totient is φ = 20708756376.

The previous prime is 21650063993. The next prime is 21650064041. The reversal of 21650064013 is 31046005612.

It can be written as a sum of positive squares in only one way, i.e., 19337127364 + 2312936649 = 139058^2 + 48093^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21650064013 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 (21650065013) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 20462670 + ... + 20463727.

Almost surely, 2^21650064013 is an apocalyptic number.

21650064013 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21650064013 is a deficient number, since it is larger than the sum of its proper divisors (982234081).

21650064013 is an equidigital number, since it uses as much as digits as its factorization.

21650064013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40926443 (or 40926420 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

Adding to 21650064013 its reverse (31046005612), we get a palindrome (52696069625).

The spelling of 21650064013 in words is "twenty-one billion, six hundred fifty million, sixty-four thousand, thirteen".