21929784144 has 80 divisors (see below), whose sum is σ = 59268706560. Its totient is φ = 6979870720.

The previous prime is 21929784133. The next prime is 21929784167. The reversal of 21929784144 is 44148792912.

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, 26049 + ... + 211040.

It is an arithmetic number, because the mean of its divisors is an integer number (740858832).

Almost surely, 2^21929784144 is an apocalyptic number.

21929784144 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21929784144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29634353280).

21929784144 is an abundant number, since it is smaller than the sum of its proper divisors (37338922416).

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

21929784144 is a wasteful number, since it uses less digits than its factorization.

21929784144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237188 (or 237182 counting only the distinct ones).

The product of its digits is 1161216, while the sum is 51.

The spelling of 21929784144 in words is "twenty-one billion, nine hundred twenty-nine million, seven hundred eighty-four thousand, one hundred forty-four".