21020010102 has 216 divisors, whose sum is σ = 59231390400. Its totient is φ = 5363729280.

The previous prime is 21020010059. The next prime is 21020010103. The reversal of 21020010102 is 20101002012.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020010103) by changing a digit.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 4618524 + ... + 4623072.

It is an arithmetic number, because the mean of its divisors is an integer number (274219400).

Almost surely, 2^21020010102 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21020010102, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29615695200).

21020010102 is an abundant number, since it is smaller than the sum of its proper divisors (38211380298).

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

21020010102 is a wasteful number, since it uses less digits than its factorization.

21020010102 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4628 (or 4605 counting only the distinct ones).

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

Adding to 21020010102 its reverse (20101002012), we get a palindrome (41121012114).

The spelling of 21020010102 in words is "twenty-one billion, twenty million, ten thousand, one hundred two".