21001000110020 has 72 divisors (see below), whose sum is σ = 51773108005080. Its totient is φ = 7134284666880.

The previous prime is 21001000110007. The next prime is 21001000110029. The reversal of 21001000110020 is 2001100010012.

It can be written as a sum of positive squares in 4 ways, for example, as 5684609914564 + 15316390195456 = 2384242^2 + 3913616^2 .

It is not an unprimeable number, because it can be changed into a prime (21001000110029) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 98194061 + ... + 98407700.

It is an arithmetic number, because the mean of its divisors is an integer number (719070944515).

Almost surely, 2^{21001000110020} is an apocalyptic number.

21001000110020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001000110020 is an abundant number, since it is smaller than the sum of its proper divisors (30772107895060).

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

21001000110020 is a wasteful number, since it uses less digits than its factorization.

21001000110020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196601893 (or 196601884 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 21001000110020 its reverse (2001100010012), we get a palindrome (23002100120032).

The spelling of 21001000110020 in words is "twenty-one trillion, one billion, one hundred ten thousand, twenty".