21155055080 has 64 divisors (see below), whose sum is σ = 47858556240. Its totient is φ = 8415977472.

The previous prime is 21155055079. The next prime is 21155055109. The reversal of 21155055080 is 8055055112.

It can be written as a sum of positive squares in 8 ways, for example, as 459930916 + 20695124164 = 21446^2 + 143858^2 .

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 15 ways as a sum of consecutive naturals, for example, 7455422 + ... + 7458258.

Almost surely, 2^21155055080 is an apocalyptic number.

21155055080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21155055080 is an abundant number, since it is smaller than the sum of its proper divisors (26703501160).

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

21155055080 is a wasteful number, since it uses less digits than its factorization.

21155055080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3798 (or 3794 counting only the distinct ones).

The product of its (nonzero) digits is 10000, while the sum is 32.

Adding to 21155055080 its sum of digits (32), we get a palindrome (21155055112).

The spelling of 21155055080 in words is "twenty-one billion, one hundred fifty-five million, fifty-five thousand, eighty".