210001021020 has 144 divisors (see below), whose sum is σ = 729281000448. Its totient is φ = 47916005760.

The previous prime is 210001021019. The next prime is 210001021031. The reversal of 210001021020 is 20120100012.

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

It is a junction number, because it is equal to n+sod(n) for n = 210001020993 and 210001021011.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 573517 + ... + 865403.

It is an arithmetic number, because the mean of its divisors is an integer number (5064451392).

Almost surely, 2^210001021020 is an apocalyptic number.

210001021020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 210001021020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (364640500224).

210001021020 is an abundant number, since it is smaller than the sum of its proper divisors (519279979428).

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

210001021020 is a wasteful number, since it uses less digits than its factorization.

210001021020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292480 (or 292475 counting only the distinct ones).

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

Adding to 210001021020 its reverse (20120100012), we get a palindrome (230121121032).

The spelling of 210001021020 in words is "two hundred ten billion, one million, twenty-one thousand, twenty".