21965723208 has 320 divisors, whose sum is σ = 73027120320. Its totient is φ = 6080832000.

The previous prime is 21965723177. The next prime is 21965723251. The reversal of 21965723208 is 80232756912.

It is a super-2 number, since 2×21965723208² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 9357891 + ... + 9360237.

It is an arithmetic number, because the mean of its divisors is an integer number (228209751).

Almost surely, 2^21965723208 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 21965723208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36513560160).

21965723208 is an abundant number, since it is smaller than the sum of its proper divisors (51061397112).

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

21965723208 is a wasteful number, since it uses less digits than its factorization.

21965723208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2490 (or 2477 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 21965723208 in words is "twenty-one billion, nine hundred sixty-five million, seven hundred twenty-three thousand, two hundred eight".