21797717760 has 1152 divisors, whose sum is σ = 98896896000. Its totient is φ = 4421910528.

The previous prime is 21797717743. The next prime is 21797717761. The reversal of 21797717760 is 6771779712.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (1152).

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

It is a junction number, because it is equal to n+sod(n) for n = 21797717697 and 21797717706.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21797717761) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 91203721 + ... + 91203959.

It is an arithmetic number, because the mean of its divisors is an integer number (85848000).

Almost surely, 2^21797717760 is an apocalyptic number.

21797717760 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 21797717760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49448448000).

21797717760 is an abundant number, since it is smaller than the sum of its proper divisors (77099178240).

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

21797717760 is a wasteful number, since it uses less digits than its factorization.

21797717760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318 (or 298 counting only the distinct ones).

The product of its (nonzero) digits is 1815156, while the sum is 54.

The spelling of 21797717760 in words is "twenty-one billion, seven hundred ninety-seven million, seven hundred seventeen thousand, seven hundred sixty".