21003240208 has 20 divisors (see below), whose sum is σ = 40715109468. Its totient is φ = 10496115200.

The previous prime is 21003240077. The next prime is 21003240233. The reversal of 21003240208 is 80204230012.

It can be written as a sum of positive squares in 2 ways, for example, as 19323224064 + 1680016144 = 139008^2 + 40988^2 .

It is a super-2 number, since 2×21003240208² (a number of 21 digits) contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 312493 + ... + 373708.

Almost surely, 2^21003240208 is an apocalyptic number.

It is an amenable number.

21003240208 is a deficient number, since it is larger than the sum of its proper divisors (19711869260).

21003240208 is a wasteful number, since it uses less digits than its factorization.

21003240208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 688122 (or 688116 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

The spelling of 21003240208 in words is "twenty-one billion, three million, two hundred forty thousand, two hundred eight".