21664523310105 has 16 divisors (see below), whose sum is σ = 37329640165440. Its totient is φ = 10665611475648.

The previous prime is 21664523310103. The next prime is 21664523310109. The reversal of 21664523310105 is 50101332546612.

It is a happy number.

It is not a de Polignac number, because 21664523310105 - 2¹ = 21664523310103 is a prime.

It is a super-2 number, since 2×21664523310105² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (21664523310103) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55550059575 + ... + 55550059964.

It is an arithmetic number, because the mean of its divisors is an integer number (2333102510340).

Almost surely, 2^{21664523310105} is an apocalyptic number.

It is an amenable number.

21664523310105 is a deficient number, since it is larger than the sum of its proper divisors (15665116855335).

21664523310105 is a wasteful number, since it uses less digits than its factorization.

21664523310105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111100119560.

The product of its (nonzero) digits is 129600, while the sum is 39.

Adding to 21664523310105 its reverse (50101332546612), we get a palindrome (71765855856717).

The spelling of 21664523310105 in words is "twenty-one trillion, six hundred sixty-four billion, five hundred twenty-three million, three hundred ten thousand, one hundred five".