21055123331550 has 384 divisors, whose sum is σ = 75479831838720. Its totient is φ = 4184868758400.

The previous prime is 21055123331531. The next prime is 21055123331551. The reversal of 21055123331550 is 5513332155012.

21055123331550 is a `hidden beast` number, since 2 + 1 + 0 + 5 + 51 + 23 + 3 + 31 + 550 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21055123331551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 2012422 + ... + 6794121.

It is an arithmetic number, because the mean of its divisors is an integer number (196562062080).

Almost surely, 2^{21055123331550} is an apocalyptic number.

21055123331550 is an abundant number, since it is smaller than the sum of its proper divisors (54424708507170).

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

21055123331550 is a wasteful number, since it uses less digits than its factorization.

21055123331550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8806605 (or 8806594 counting only the distinct ones).

The product of its (nonzero) digits is 67500, while the sum is 36.

Adding to 21055123331550 its reverse (5513332155012), we get a palindrome (26568455486562).

The spelling of 21055123331550 in words is "twenty-one trillion, fifty-five billion, one hundred twenty-three million, three hundred thirty-one thousand, five hundred fifty".