20021000020 has 48 divisors (see below), whose sum is σ = 48658659840. Its totient is φ = 6777448704.

The previous prime is 20020999951. The next prime is 20021000047. The reversal of 20021000020 is 2000012002.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (7).

It is a junction number, because it is equal to n+sod(n) for n = 20020999967 and 20021000012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 894049 + ... + 916168.

It is an arithmetic number, because the mean of its divisors is an integer number (1013722080).

Almost surely, 2^20021000020 is an apocalyptic number.

20021000020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20021000020 is an abundant number, since it is smaller than the sum of its proper divisors (28637659820).

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

20021000020 is a wasteful number, since it uses less digits than its factorization.

20021000020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1810312 (or 1810310 counting only the distinct ones).

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

Adding to 20021000020 its reverse (2000012002), we get a palindrome (22021012022).

The spelling of 20021000020 in words is "twenty billion, twenty-one million, twenty", and thus it is an aban number and an uban number.