1021000020 has 48 divisors (see below), whose sum is σ = 2860404288. Its totient is φ = 272113920.

The previous prime is 1021000009. The next prime is 1021000027. The reversal of 1021000020 is 200001201.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a junction number, because it is equal to n+sod(n) for n = 1020999972 and 1021000008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021000027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 138672 + ... + 145848.

It is an arithmetic number, because the mean of its divisors is an integer number (59591756).

Almost surely, 2^1021000020 is an apocalyptic number.

1021000020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1021000020 is an abundant number, since it is smaller than the sum of its proper divisors (1839404268).

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

1021000020 is a wasteful number, since it uses less digits than its factorization.

1021000020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9560 (or 9558 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 6.

The square root of 1021000020 is about 31953.0909302997. The cubic root of 1021000020 is about 1006.9515703595.

Adding to 1021000020 its reverse (200001201), we get a palindrome (1221001221).

The spelling of 1021000020 in words is "one billion, twenty-one million, twenty", and thus it is an aban number and an uban number.