210001220100020 has 48 divisors (see below), whose sum is σ = 466991058170448. Its totient is φ = 79051296614400.

The previous prime is 210001220100017. The next prime is 210001220100029. The reversal of 210001220100020 is 20001022100012.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 21007243889956 + 188993976210064 = 4583366^2 + 13747508^2 .

It is a junction number, because it is equal to n+sod(n) for n = 210001220099974 and 210001220100010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210001220100029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27824987 + ... + 34557666.

It is an arithmetic number, because the mean of its divisors is an integer number (9728980378551).

Almost surely, 2^{210001220100020} is an apocalyptic number.

210001220100020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

210001220100020 is an abundant number, since it is smaller than the sum of its proper divisors (256989838070428).

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

210001220100020 is a wasteful number, since it uses less digits than its factorization.

210001220100020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62392580 (or 62392578 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 210001220100020 its reverse (20001022100012), we get a palindrome (230002242200032).

The spelling of 210001220100020 in words is "two hundred ten trillion, one billion, two hundred twenty million, one hundred thousand, twenty".