20021000000020 has 24 divisors (see below), whose sum is σ = 42516505621800. Its totient is φ = 7918417976832.

The previous prime is 20020999999991. The next prime is 20021000000021. The reversal of 20021000000020 is 2000000012002.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 721110069124 + 19299889930896 = 849182^2 + 4393164^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021000000021) 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, 5623874625 + ... + 5623878184.

It is an arithmetic number, because the mean of its divisors is an integer number (1771521067575).

Almost surely, 2^{20021000000020} is an apocalyptic number.

20021000000020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20021000000020 is an abundant number, since it is smaller than the sum of its proper divisors (22495505621780).

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

20021000000020 is a wasteful number, since it uses less digits than its factorization.

20021000000020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11247752907 (or 11247752905 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 7.

Adding to 20021000000020 its reverse (2000000012002), we get a palindrome (22021000012022).

The spelling of 20021000000020 in words is "twenty trillion, twenty-one billion, twenty", and thus it is an aban number and an uban number.