21956767872 has 256 divisors, whose sum is σ = 64486195200. Its totient is φ = 6577901568.

The previous prime is 21956767853. The next prime is 21956767879. The reversal of 21956767872 is 27876765912.

It is not an unprimeable number, because it can be changed into a prime (21956767879) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 37404763 + ... + 37405349.

It is an arithmetic number, because the mean of its divisors is an integer number (251899200).

Almost surely, 2^21956767872 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 21956767872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32243097600).

21956767872 is an abundant number, since it is smaller than the sum of its proper divisors (42529427328).

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

21956767872 is a wasteful number, since it uses less digits than its factorization.

21956767872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 803 (or 791 counting only the distinct ones).

The product of its digits is 17781120, while the sum is 60.

The spelling of 21956767872 in words is "twenty-one billion, nine hundred fifty-six million, seven hundred sixty-seven thousand, eight hundred seventy-two".