20105421520 has 40 divisors (see below), whose sum is σ = 49205377440. Its totient is φ = 7618896000.

The previous prime is 20105421499. The next prime is 20105421529. The reversal of 20105421520 is 2512450102.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×20105421520² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20105421491 and 20105421500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20105421529) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6612106 + ... + 6615145.

It is an arithmetic number, because the mean of its divisors is an integer number (1230134436).

Almost surely, 2^20105421520 is an apocalyptic number.

20105421520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20105421520 is an abundant number, since it is smaller than the sum of its proper divisors (29099955920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20105421520 is a wasteful number, since it uses less digits than its factorization.

20105421520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13227283 (or 13227277 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 22.

Adding to 20105421520 its reverse (2512450102), we get a palindrome (22617871622).

The spelling of 20105421520 in words is "twenty billion, one hundred five million, four hundred twenty-one thousand, five hundred twenty".