20021100020 has 24 divisors (see below), whose sum is σ = 42516721800. Its totient is φ = 7918456832.

The previous prime is 20021100019. The next prime is 20021100023. The reversal of 20021100020 is 2000112002.

It can be written as a sum of positive squares in 4 ways, for example, as 3396092176 + 16625007844 = 58276^2 + 128938^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20021099980 and 20021100007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021100023) 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, 5622125 + ... + 5625684.

It is an arithmetic number, because the mean of its divisors is an integer number (1771530075).

Almost surely, 2^20021100020 is an apocalyptic number.

20021100020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20021100020 is an abundant number, since it is smaller than the sum of its proper divisors (22495621780).

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

20021100020 is a wasteful number, since it uses less digits than its factorization.

20021100020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11247907 (or 11247905 counting only the distinct ones).

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

Adding to 20021100020 its reverse (2000112002), we get a palindrome (22021212022).

The spelling of 20021100020 in words is "twenty billion, twenty-one million, one hundred thousand, twenty".