21009406008 has 64 divisors (see below), whose sum is σ = 54748344960. Its totient is φ = 6712142976.

The previous prime is 21009406003. The next prime is 21009406037. The reversal of 21009406008 is 80060490012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21009406001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 117066 + ... + 236057.

It is an arithmetic number, because the mean of its divisors is an integer number (855442890).

Almost surely, 2^21009406008 is an apocalyptic number.

It is an amenable number.

21009406008 is an abundant number, since it is smaller than the sum of its proper divisors (33738938952).

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

21009406008 is a wasteful number, since it uses less digits than its factorization.

21009406008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 353236 (or 353232 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The spelling of 21009406008 in words is "twenty-one billion, nine million, four hundred six thousand, eight".