21693648613 has 16 divisors (see below), whose sum is σ = 27037857280. Its totient is φ = 16946931456.

The previous prime is 21693648569. The next prime is 21693648619. The reversal of 21693648613 is 31684639612.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-21693648613 is a prime.

It is a super-2 number, since 2×21693648613² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21693648619) 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 15 ways as a sum of consecutive naturals, for example, 1501620 + ... + 1515997.

It is an arithmetic number, because the mean of its divisors is an integer number (1689866080).

Almost surely, 2^21693648613 is an apocalyptic number.

It is an amenable number.

21693648613 is a deficient number, since it is larger than the sum of its proper divisors (5344208667).

21693648613 is a wasteful number, since it uses less digits than its factorization.

21693648613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3017716.

The product of its digits is 1119744, while the sum is 49.

Subtracting 21693648613 from its reverse (31684639612), we obtain a palindrome (9990990999).

The spelling of 21693648613 in words is "twenty-one billion, six hundred ninety-three million, six hundred forty-eight thousand, six hundred thirteen".