21550320520 has 16 divisors (see below), whose sum is σ = 48488221260. Its totient is φ = 8620128192.

The previous prime is 21550320469. The next prime is 21550320527. The reversal of 21550320520 is 2502305512.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20875048324 + 675272196 = 144482^2 + 25986^2 .

It is not an unprimeable number, because it can be changed into a prime (21550320527) 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 3 ways as a sum of consecutive naturals, for example, 269378967 + ... + 269379046.

Almost surely, 2^21550320520 is an apocalyptic number.

21550320520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21550320520 is an abundant number, since it is smaller than the sum of its proper divisors (26937900740).

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

21550320520 is a wasteful number, since it uses less digits than its factorization.

21550320520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 538758024 (or 538758020 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 25.

The spelling of 21550320520 in words is "twenty-one billion, five hundred fifty million, three hundred twenty thousand, five hundred twenty".