21279016208 has 20 divisors (see below), whose sum is σ = 41238206940. Its totient is φ = 10636898304.

The previous prime is 21279016183. The next prime is 21279016211. The reversal of 21279016208 is 80261097212.

It can be written as a sum of positive squares in 2 ways, for example, as 14334793984 + 6944222224 = 119728^2 + 83332^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 94985 + ... + 227112.

It is an arithmetic number, because the mean of its divisors is an integer number (2061910347).

Almost surely, 2^21279016208 is an apocalyptic number.

It is an amenable number.

21279016208 is a deficient number, since it is larger than the sum of its proper divisors (19959190732).

21279016208 is a wasteful number, since it uses less digits than its factorization.

21279016208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 326234 (or 326228 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 38.

The spelling of 21279016208 in words is "twenty-one billion, two hundred seventy-nine million, sixteen thousand, two hundred eight".