21520414140 has 96 divisors (see below), whose sum is σ = 63122734080. Its totient is φ = 5467815936.

The previous prime is 21520414133. The next prime is 21520414141. The reversal of 21520414140 is 4141402512.

It is a super-2 number, since 2×21520414140² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21520414140.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21520414141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 324321 + ... + 384999.

It is an arithmetic number, because the mean of its divisors is an integer number (657528480).

Almost surely, 2^21520414140 is an apocalyptic number.

21520414140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21520414140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31561367040).

21520414140 is an abundant number, since it is smaller than the sum of its proper divisors (41602319940).

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

21520414140 is a wasteful number, since it uses less digits than its factorization.

21520414140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60971 (or 60969 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

Adding to 21520414140 its reverse (4141402512), we get a palindrome (25661816652).

The spelling of 21520414140 in words is "twenty-one billion, five hundred twenty million, four hundred fourteen thousand, one hundred forty".