21115743600 has 240 divisors, whose sum is σ = 77827161600. Its totient is φ = 4793779200.

The previous prime is 21115743491. The next prime is 21115743611. The reversal of 21115743600 is 634751112.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (30).

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 47 ways as a sum of consecutive naturals, for example, 1243165 + ... + 1260035.

It is an arithmetic number, because the mean of its divisors is an integer number (324279840).

Almost surely, 2^21115743600 is an apocalyptic number.

21115743600 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 21115743600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38913580800).

21115743600 is an abundant number, since it is smaller than the sum of its proper divisors (56711418000).

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

21115743600 is a wasteful number, since it uses less digits than its factorization.

21115743600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17048 (or 17037 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 30.

The spelling of 21115743600 in words is "twenty-one billion, one hundred fifteen million, seven hundred forty-three thousand, six hundred".