21110511912 has 256 divisors, whose sum is σ = 65138688000. Its totient is φ = 5570104320.

The previous prime is 21110511901. The next prime is 21110511913. The reversal of 21110511912 is 21911501112.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (21110511913) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 21301737 + ... + 21302727.

It is an arithmetic number, because the mean of its divisors is an integer number (254448000).

Almost surely, 2^21110511912 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21110511912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32569344000).

21110511912 is an abundant number, since it is smaller than the sum of its proper divisors (44028176088).

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

21110511912 is a wasteful number, since it uses less digits than its factorization.

21110511912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1216 (or 1212 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 24.

The spelling of 21110511912 in words is "twenty-one billion, one hundred ten million, five hundred eleven thousand, nine hundred twelve".