21067828668 has 54 divisors (see below), whose sum is σ = 54061914816. Its totient is φ = 6917741424.

The previous prime is 21067828667. The next prime is 21067828681. The reversal of 21067828668 is 86682876012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21067828667) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 96421 + ... + 226787.

Almost surely, 2^21067828668 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21067828668, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27030957408).

21067828668 is an abundant number, since it is smaller than the sum of its proper divisors (32994086148).

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

21067828668 is a wasteful number, since it uses less digits than its factorization.

21067828668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130511 (or 130439 counting only the distinct ones).

The product of its (nonzero) digits is 3096576, while the sum is 54.

The spelling of 21067828668 in words is "twenty-one billion, sixty-seven million, eight hundred twenty-eight thousand, six hundred sixty-eight".