21000111208 has 8 divisors (see below), whose sum is σ = 39375208530. Its totient is φ = 10500055600.

The previous prime is 21000111179. The next prime is 21000111227. The reversal of 21000111208 is 80211100012.

It can be written as a sum of positive squares in only one way, i.e., 15644506084 + 5355605124 = 125078^2 + 73182^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 21000111191 and 21000111200.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1312506943 + ... + 1312506958.

Almost surely, 2^21000111208 is an apocalyptic number.

It is an amenable number.

21000111208 is a deficient number, since it is larger than the sum of its proper divisors (18375097322).

21000111208 is a wasteful number, since it uses less digits than its factorization.

21000111208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2625013907 (or 2625013903 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

The spelling of 21000111208 in words is "twenty-one billion, one hundred eleven thousand, two hundred eight".