21112757680 has 80 divisors (see below), whose sum is σ = 56164887360. Its totient is φ = 7230237696.

The previous prime is 21112757671. The next prime is 21112757681. The reversal of 21112757680 is 8675721112.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (21112757681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 469626 + ... + 512614.

It is an arithmetic number, because the mean of its divisors is an integer number (702061092).

Almost surely, 2^21112757680 is an apocalyptic number.

21112757680 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 21112757680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28082443680).

21112757680 is an abundant number, since it is smaller than the sum of its proper divisors (35052129680).

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

21112757680 is a wasteful number, since it uses less digits than its factorization.

21112757680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43886 (or 43880 counting only the distinct ones).

The product of its (nonzero) digits is 47040, while the sum is 40.

The spelling of 21112757680 in words is "twenty-one billion, one hundred twelve million, seven hundred fifty-seven thousand, six hundred eighty".