21550129440 has 288 divisors, whose sum is σ = 79383737664. Its totient is φ = 4899686400.

The previous prime is 21550129421. The next prime is 21550129487. The reversal of 21550129440 is 4492105512.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4631115 + ... + 4635765.

It is an arithmetic number, because the mean of its divisors is an integer number (275637978).

Almost surely, 2^21550129440 is an apocalyptic number.

21550129440 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 21550129440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39691868832).

21550129440 is an abundant number, since it is smaller than the sum of its proper divisors (57833608224).

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

21550129440 is a wasteful number, since it uses less digits than its factorization.

21550129440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4880 (or 4865 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 33.

The spelling of 21550129440 in words is "twenty-one billion, five hundred fifty million, one hundred twenty-nine thousand, four hundred forty".