21244520105 has 4 divisors (see below), whose sum is σ = 25493424132. Its totient is φ = 16995616080.

The previous prime is 21244520093. The next prime is 21244520117. The reversal of 21244520105 is 50102544212.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21244520093) and next prime (21244520117).

It can be written as a sum of positive squares in 2 ways, for example, as 12085264489 + 9159255616 = 109933^2 + 95704^2 .

It is not a de Polignac number, because 21244520105 - 2⁶ = 21244520041 is a prime.

It is a super-2 number, since 2×21244520105² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 2124452006 + ... + 2124452015.

It is an arithmetic number, because the mean of its divisors is an integer number (6373356033).

Almost surely, 2^21244520105 is an apocalyptic number.

It is an amenable number.

21244520105 is a deficient number, since it is larger than the sum of its proper divisors (4248904027).

21244520105 is an equidigital number, since it uses as much as digits as its factorization.

21244520105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4248904026.

The product of its (nonzero) digits is 3200, while the sum is 26.

The spelling of 21244520105 in words is "twenty-one billion, two hundred forty-four million, five hundred twenty thousand, one hundred five".