21138828480 has 1344 divisors, whose sum is σ = 99281894400. Its totient is φ = 3994583040.

The previous prime is 21138828457. The next prime is 21138828497. The reversal of 21138828480 is 8482883112.

It is a happy number.

21138828480 is a `hidden beast` number, since 211 + 3 + 88 + 284 + 80 = 666.

It is a tau number, because it is divible by the number of its divisors (1344).

It is a super-2 number, since 2×21138828480² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 122189674 + ... + 122189846.

Almost surely, 2^21138828480 is an apocalyptic number.

21138828480 is a gapful number since it is divisible by the number (20) 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 21138828480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49640947200).

21138828480 is an abundant number, since it is smaller than the sum of its proper divisors (78143065920).

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

21138828480 is a wasteful number, since it uses less digits than its factorization.

21138828480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262 (or 249 counting only the distinct ones).

The product of its (nonzero) digits is 196608, while the sum is 45.

The spelling of 21138828480 in words is "twenty-one billion, one hundred thirty-eight million, eight hundred twenty-eight thousand, four hundred eighty".