21909479317440 has 896 divisors, whose sum is σ = 85384156741632. Its totient is φ = 4683768545280.

The previous prime is 21909479317351. The next prime is 21909479317483. The reversal of 21909479317440 is 4471397490912.

It is a happy number.

It is a super-2 number, since 2×21909479317440² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 2800645369 + ... + 2800653191.

It is an arithmetic number, because the mean of its divisors is an integer number (95294817792).

Almost surely, 2^{21909479317440} is an apocalyptic number.

21909479317440 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 21909479317440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42692078370816).

21909479317440 is an abundant number, since it is smaller than the sum of its proper divisors (63474677424192).

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

21909479317440 is a wasteful number, since it uses less digits than its factorization.

21909479317440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8777 (or 8767 counting only the distinct ones).

The product of its (nonzero) digits is 13716864, while the sum is 60.

The spelling of 21909479317440 in words is "twenty-one trillion, nine hundred nine billion, four hundred seventy-nine million, three hundred seventeen thousand, four hundred forty".