21797318880 has 144 divisors (see below), whose sum is σ = 74450638080. Its totient is φ = 5807361024.

The previous prime is 21797318771. The next prime is 21797318903. The reversal of 21797318880 is 8881379712.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×21797318880² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1740481 + ... + 1752959.

It is an arithmetic number, because the mean of its divisors is an integer number (517018320).

Almost surely, 2^21797318880 is an apocalyptic number.

21797318880 is a gapful number since it is divisible by the number (20) 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 21797318880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37225319040).

21797318880 is an abundant number, since it is smaller than the sum of its proper divisors (52653319200).

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

21797318880 is a wasteful number, since it uses less digits than its factorization.

21797318880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13713 (or 13702 counting only the distinct ones).

The product of its (nonzero) digits is 1354752, while the sum is 54.

The spelling of 21797318880 in words is "twenty-one billion, seven hundred ninety-seven million, three hundred eighteen thousand, eight hundred eighty".