21016017208 has 8 divisors (see below), whose sum is σ = 39405032280. Its totient is φ = 10508008600.

The previous prime is 21016017199. The next prime is 21016017247. The reversal of 21016017208 is 80271061012.

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

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1313501068 + ... + 1313501083.

It is an arithmetic number, because the mean of its divisors is an integer number (4925629035).

Almost surely, 2^21016017208 is an apocalyptic number.

It is an amenable number.

21016017208 is a deficient number, since it is larger than the sum of its proper divisors (18389015072).

21016017208 is a wasteful number, since it uses less digits than its factorization.

21016017208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2627002157 (or 2627002153 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 28.

The spelling of 21016017208 in words is "twenty-one billion, sixteen million, seventeen thousand, two hundred eight".