21330053550 has 144 divisors (see below), whose sum is σ = 61804950480. Its totient is φ = 5242821120.

The previous prime is 21330053539. The next prime is 21330053587. The reversal of 21330053550 is 5535003312.

21330053550 is a `hidden beast` number, since 2 + 1 + 3 + 300 + 5 + 355 + 0 = 666.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 4730397 + ... + 4734903.

It is an arithmetic number, because the mean of its divisors is an integer number (429201045).

Almost surely, 2^21330053550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21330053550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30902475240).

21330053550 is an abundant number, since it is smaller than the sum of its proper divisors (40474896930).

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

21330053550 is a wasteful number, since it uses less digits than its factorization.

21330053550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5347 (or 5339 counting only the distinct ones).

The product of its (nonzero) digits is 6750, while the sum is 27.

Adding to 21330053550 its reverse (5535003312), we get a palindrome (26865056862).

The spelling of 21330053550 in words is "twenty-one billion, three hundred thirty million, fifty-three thousand, five hundred fifty".