21891735012 has 96 divisors (see below), whose sum is σ = 60745531392. Its totient is φ = 6006139776.

The previous prime is 21891735007. The next prime is 21891735043. The reversal of 21891735012 is 21053719812.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 156933 + ... + 261555.

It is an arithmetic number, because the mean of its divisors is an integer number (632765952).

Almost surely, 2^21891735012 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 21891735012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30372765696).

21891735012 is an abundant number, since it is smaller than the sum of its proper divisors (38853796380).

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

21891735012 is a wasteful number, since it uses less digits than its factorization.

21891735012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104737 (or 104735 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 39.

The spelling of 21891735012 in words is "twenty-one billion, eight hundred ninety-one million, seven hundred thirty-five thousand, twelve".