1021100020 has 24 divisors (see below), whose sum is σ = 2180656800. Its totient is φ = 401516832.

The previous prime is 1021100011. The next prime is 1021100021. The reversal of 1021100020 is 200011201.

It is a junction number, because it is equal to n+sod(n) for n = 1021099976 and 1021100012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021100021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 431490 + ... + 433849.

It is an arithmetic number, because the mean of its divisors is an integer number (90860700).

Almost surely, 2^1021100020 is an apocalyptic number.

1021100020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1021100020 is an abundant number, since it is smaller than the sum of its proper divisors (1159556780).

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

1021100020 is a wasteful number, since it uses less digits than its factorization.

1021100020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 865407 (or 865405 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 1021100020 is about 31954.6556858308. The cubic root of 1021100020 is about 1006.9844439697.

Adding to 1021100020 its reverse (200011201), we get a palindrome (1221111221).

The spelling of 1021100020 in words is "one billion, twenty-one million, one hundred thousand, twenty".