201021000020 has 24 divisors (see below), whose sum is σ = 432440299368. Its totient is φ = 78447219200.

The previous prime is 201021000013. The next prime is 201021000029. The reversal of 201021000020 is 20000120102.

It can be written as a sum of positive squares in 4 ways, for example, as 16461403204 + 184559596816 = 128302^2 + 429604^2 .

It is a junction number, because it is equal to n+sod(n) for n = 201020999971 and 201021000007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201021000029) 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, 122572961 + ... + 122574600.

It is an arithmetic number, because the mean of its divisors is an integer number (18018345807).

Almost surely, 2^201021000020 is an apocalyptic number.

201021000020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

201021000020 is an abundant number, since it is smaller than the sum of its proper divisors (231419299348).

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

201021000020 is a wasteful number, since it uses less digits than its factorization.

201021000020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245147611 (or 245147609 counting only the distinct ones).

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

Adding to 201021000020 its reverse (20000120102), we get a palindrome (221021120122).

The spelling of 201021000020 in words is "two hundred one billion, twenty-one million, twenty", and thus it is an aban number.