21974727816 has 320 divisors, whose sum is σ = 66784798080. Its totient is φ = 6725928960.

The previous prime is 21974727791. The next prime is 21974727823. The reversal of 21974727816 is 61872747912.

21974727816 is a `hidden beast` number, since 2 + 1 + 97 + 472 + 7 + 81 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

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, 121407246 + ... + 121407426.

It is an arithmetic number, because the mean of its divisors is an integer number (208702494).

Almost surely, 2^21974727816 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 21974727816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33392399040).

21974727816 is an abundant number, since it is smaller than the sum of its proper divisors (44810070264).

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

21974727816 is a wasteful number, since it uses less digits than its factorization.

21974727816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 426 (or 413 counting only the distinct ones).

The product of its digits is 2370816, while the sum is 54.

The spelling of 21974727816 in words is "twenty-one billion, nine hundred seventy-four million, seven hundred twenty-seven thousand, eight hundred sixteen".