21210012008 has 16 divisors (see below), whose sum is σ = 39799788480. Its totient is φ = 10596735088.

The previous prime is 21210012001. The next prime is 21210012013. The reversal of 21210012008 is 80021001212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21210012001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1022960 + ... + 1043487.

It is an arithmetic number, because the mean of its divisors is an integer number (2487486780).

Almost surely, 2^21210012008 is an apocalyptic number.

It is an amenable number.

21210012008 is a deficient number, since it is larger than the sum of its proper divisors (18589776472).

21210012008 is a wasteful number, since it uses less digits than its factorization.

21210012008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2067736 (or 2067732 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

The spelling of 21210012008 in words is "twenty-one billion, two hundred ten million, twelve thousand, eight".