21120616944 has 640 divisors, whose sum is σ = 78509260800. Its totient is φ = 5295144960.

The previous prime is 21120616879. The next prime is 21120617027. The reversal of 21120616944 is 44961602112.

21120616944 is a `hidden beast` number, since 2 + 11 + 20 + 616 + 9 + 4 + 4 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 21120616899 and 21120616908.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 46215564 + ... + 46216020.

It is an arithmetic number, because the mean of its divisors is an integer number (122670720).

Almost surely, 2^21120616944 is an apocalyptic number.

21120616944 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 21120616944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39254630400).

21120616944 is an abundant number, since it is smaller than the sum of its proper divisors (57388643856).

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

21120616944 is a wasteful number, since it uses less digits than its factorization.

21120616944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 558 (or 546 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

It can be divided in two parts, 211206 and 16944, that added together give a triangular number (228150 = T₆₇₅).

The spelling of 21120616944 in words is "twenty-one billion, one hundred twenty million, six hundred sixteen thousand, nine hundred forty-four".