21671091008 has 84 divisors (see below), whose sum is σ = 49455397152. Its totient is φ = 9229536000.

The previous prime is 21671090999. The next prime is 21671091059. The reversal of 21671091008 is 80019017612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 49364453 + ... + 49364891.

It is an arithmetic number, because the mean of its divisors is an integer number (588754728).

Almost surely, 2^21671091008 is an apocalyptic number.

21671091008 is a gapful number since it is divisible by the number (28) 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 21671091008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24727698576).

21671091008 is an abundant number, since it is smaller than the sum of its proper divisors (27784306144).

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

21671091008 is an frugal number, since it uses more digits than its factorization.

21671091008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1148 (or 699 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 35.

The spelling of 21671091008 in words is "twenty-one billion, six hundred seventy-one million, ninety-one thousand, eight".