21021087168 has 112 divisors (see below), whose sum is σ = 62122629120. Its totient is φ = 6970233600.

The previous prime is 21021087151. The next prime is 21021087181. The reversal of 21021087168 is 86178012012.

It is a super-2 number, since 2×21021087168² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

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, 298203 + ... + 361893.

Almost surely, 2^21021087168 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 21021087168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31061314560).

21021087168 is an abundant number, since it is smaller than the sum of its proper divisors (41101541952).

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

21021087168 is a wasteful number, since it uses less digits than its factorization.

21021087168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63903 (or 63887 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 36.

The spelling of 21021087168 in words is "twenty-one billion, twenty-one million, eighty-seven thousand, one hundred sixty-eight".