21073223808 has 648 divisors, whose sum is σ = 78044272605. Its totient is φ = 5439522816.

The previous prime is 21073223777. The next prime is 21073223813. The reversal of 21073223808 is 80832237012.

It is a happy number.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 18018229824 + 3054993984 = 134232^2 + 55272^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=102648.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 448366441 + ... + 448366487.

Almost surely, 2^21073223808 is an apocalyptic number.

21073223808 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 21073223808

21073223808 is an abundant number, since it is smaller than the sum of its proper divisors (56971048797).

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

21073223808 is a wasteful number, since it uses less digits than its factorization.

21073223808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154 (or 72 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The spelling of 21073223808 in words is "twenty-one billion, seventy-three million, two hundred twenty-three thousand, eight hundred eight".