21002010102 has 64 divisors (see below), whose sum is σ = 48751488000. Its totient is φ = 6689257344.

The previous prime is 21002010059. The next prime is 21002010131. The reversal of 21002010102 is 20101020012.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1244799 + ... + 1261557.

It is an arithmetic number, because the mean of its divisors is an integer number (761742000).

Almost surely, 2^21002010102 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21002010102, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24375744000).

21002010102 is an abundant number, since it is smaller than the sum of its proper divisors (27749477898).

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

21002010102 is a wasteful number, since it uses less digits than its factorization.

21002010102 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17802 (or 17796 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21002010102 its reverse (20101020012), we get a palindrome (41103030114).

The spelling of 21002010102 in words is "twenty-one billion, two million, ten thousand, one hundred two".