20001020010021 has 12 divisors (see below), whose sum is σ = 28890401068620. Its totient is φ = 13333995417600.

The previous prime is 20001020010007. The next prime is 20001020010031. The reversal of 20001020010021 is 12001002010002.

It can be written as a sum of positive squares in 2 ways, for example, as 12391068809025 + 7609951200996 = 3520095^2 + 2758614^2 .

It is not a de Polignac number, because 20001020010021 - 2²⁵ = 20000986455589 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 20001020009985 and 20001020010012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20001020010031) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11828971 + ... + 13413671.

It is an arithmetic number, because the mean of its divisors is an integer number (2407533422385).

Almost surely, 2^{20001020010021} is an apocalyptic number.

It is an amenable number.

20001020010021 is a deficient number, since it is larger than the sum of its proper divisors (8889381058599).

20001020010021 is a wasteful number, since it uses less digits than its factorization.

20001020010021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2987076 (or 2987073 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 20001020010021 its reverse (12001002010002), we get a palindrome (32002022020023).

The spelling of 20001020010021 in words is "twenty trillion, one billion, twenty million, ten thousand, twenty-one".