21722777216 has 128 divisors (see below), whose sum is σ = 53125680000. Its totient is φ = 8819435520.

The previous prime is 21722777183. The next prime is 21722777221. The reversal of 21722777216 is 61277722712.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 821156 + ... + 847196.

It is an arithmetic number, because the mean of its divisors is an integer number (415044375).

Almost surely, 2^21722777216 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 21722777216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26562840000).

21722777216 is an abundant number, since it is smaller than the sum of its proper divisors (31402902784).

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

21722777216 is an equidigital number, since it uses as much as digits as its factorization.

21722777216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26095 (or 26069 counting only the distinct ones).

The product of its digits is 230496, while the sum is 44.

The spelling of 21722777216 in words is "twenty-one billion, seven hundred twenty-two million, seven hundred seventy-seven thousand, two hundred sixteen".