1021000021020 has 288 divisors, whose sum is σ = 3609431280000. Its totient is φ = 228766187520.

The previous prime is 1021000021007. The next prime is 1021000021087. The reversal of 1021000021020 is 201200001201.

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 = 1021000020993 and 1021000021011.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 83402100 + ... + 83414340.

It is an arithmetic number, because the mean of its divisors is an integer number (12532747500).

Almost surely, 2^{1021000021020} is an apocalyptic number.

1021000021020 is a gapful number since it is divisible by the number (10) 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 1021000021020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1804715640000).

1021000021020 is an abundant number, since it is smaller than the sum of its proper divisors (2588431258980).

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

1021000021020 is a wasteful number, since it uses less digits than its factorization.

1021000021020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13565 (or 13560 counting only the distinct ones).

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

Adding to 1021000021020 its reverse (201200001201), we get a palindrome (1222200022221).

The spelling of 1021000021020 in words is "one trillion, twenty-one billion, twenty-one thousand, twenty".