21055520304 has 720 divisors, whose sum is σ = 77522163264. Its totient is φ = 5283532800.

The previous prime is 21055520293. The next prime is 21055520327. The reversal of 21055520304 is 40302555012.

It is a happy number.

21055520304 is a `hidden beast` number, since 2 + 105 + 5 + 520 + 30 + 4 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 296556589 + ... + 296556659.

Almost surely, 2^21055520304 is an apocalyptic number.

21055520304 is a gapful number since it is divisible by the number (24) 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 21055520304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38761081632).

21055520304 is an abundant number, since it is smaller than the sum of its proper divisors (56466642960).

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

21055520304 is a wasteful number, since it uses less digits than its factorization.

21055520304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226 (or 210 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 27.

The spelling of 21055520304 in words is "twenty-one billion, fifty-five million, five hundred twenty thousand, three hundred four".