16721687868 has 24 divisors (see below), whose sum is σ = 39140363472. Its totient is φ = 5556311424.

The previous prime is 16721687831. The next prime is 16721687881. The reversal of 16721687868 is 86878612761.

It is a happy number.

It is a super-2 number, since 2×16721687868² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2194105 + ... + 2201712.

It is an arithmetic number, because the mean of its divisors is an integer number (1630848478).

Almost surely, 2^16721687868 is an apocalyptic number.

It is an amenable number.

16721687868 is an abundant number, since it is smaller than the sum of its proper divisors (22418675604).

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

16721687868 is a wasteful number, since it uses less digits than its factorization.

16721687868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4396141 (or 4396139 counting only the distinct ones).

The product of its digits is 10838016, while the sum is 60.

The spelling of 16721687868 in words is "sixteen billion, seven hundred twenty-one million, six hundred eighty-seven thousand, eight hundred sixty-eight".