21916578684 has 144 divisors (see below), whose sum is σ = 69888099456. Its totient is φ = 5254704000.

The previous prime is 21916578683. The next prime is 21916578701. The reversal of 21916578684 is 48687561912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21916578683) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 46242 + ... + 214409.

It is an arithmetic number, because the mean of its divisors is an integer number (485334024).

Almost surely, 2^21916578684 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 21916578684, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34944049728).

21916578684 is an abundant number, since it is smaller than the sum of its proper divisors (47971520772).

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

21916578684 is a wasteful number, since it uses less digits than its factorization.

21916578684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260696 (or 260687 counting only the distinct ones).

The product of its digits is 5806080, while the sum is 57.

The spelling of 21916578684 in words is "twenty-one billion, nine hundred sixteen million, five hundred seventy-eight thousand, six hundred eighty-four".