21538082304 has 160 divisors (see below), whose sum is σ = 63940446240. Its totient is φ = 7158398976.

The previous prime is 21538082249. The next prime is 21538082309. The reversal of 21538082304 is 40328083512.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21538082309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5154264 + ... + 5158440.

It is an arithmetic number, because the mean of its divisors is an integer number (399627789).

Almost surely, 2^21538082304 is an apocalyptic number.

21538082304 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 21538082304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31970223120).

21538082304 is an abundant number, since it is smaller than the sum of its proper divisors (42402363936).

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

21538082304 is an equidigital number, since it uses as much as digits as its factorization.

21538082304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4577 (or 4555 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The spelling of 21538082304 in words is "twenty-one billion, five hundred thirty-eight million, eighty-two thousand, three hundred four".