21709434880 has 104 divisors (see below), whose sum is σ = 59539002912. Its totient is φ = 7443185664.

The previous prime is 21709434853. The next prime is 21709434889. The reversal of 21709434880 is 8843490712.

It is a super-2 number, since 2×21709434880² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21709434880.

It is not an unprimeable number, because it can be changed into a prime (21709434889) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67644 + ... + 219076.

Almost surely, 2^21709434880 is an apocalyptic number.

21709434880 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 21709434880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29769501456).

21709434880 is an abundant number, since it is smaller than the sum of its proper divisors (37829568032).

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

21709434880 is an equidigital number, since it uses as much as digits as its factorization.

21709434880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151469 (or 151447 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 46.

The spelling of 21709434880 in words is "twenty-one billion, seven hundred nine million, four hundred thirty-four thousand, eight hundred eighty".