16821445668 has 48 divisors (see below), whose sum is σ = 42084967680. Its totient is φ = 5210509824.

The previous prime is 16821445643. The next prime is 16821445717. The reversal of 16821445668 is 86654412861.

It is a super-2 number, since 2×16821445668² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a self number, because there is not a number n which added to its sum of digits gives 16821445668.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 505771 + ... + 538002.

It is an arithmetic number, because the mean of its divisors is an integer number (876770160).

Almost surely, 2^16821445668 is an apocalyptic number.

It is an amenable number.

16821445668 is an abundant number, since it is smaller than the sum of its proper divisors (25263522012).

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

16821445668 is a wasteful number, since it uses less digits than its factorization.

16821445668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1043876 (or 1043874 counting only the distinct ones).

The product of its digits is 2211840, while the sum is 51.

The spelling of 16821445668 in words is "sixteen billion, eight hundred twenty-one million, four hundred forty-five thousand, six hundred sixty-eight".