12001020021 has 80 divisors (see below), whose sum is σ = 18711285120. Its totient is φ = 7661122560.

The previous prime is 12001020019. The next prime is 12001020071. The reversal of 12001020021 is 12002010021.

It is not a de Polignac number, because 12001020021 - 2¹ = 12001020019 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 = 12001019985 and 12001020012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12001020011) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 38341761 + ... + 38342073.

It is an arithmetic number, because the mean of its divisors is an integer number (233891064).

Almost surely, 2^12001020021 is an apocalyptic number.

It is an amenable number.

12001020021 is a deficient number, since it is larger than the sum of its proper divisors (6710265099).

12001020021 is a wasteful number, since it uses less digits than its factorization.

12001020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 568 (or 559 counting only the distinct ones).

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

Adding to 12001020021 its reverse (12002010021), we get a palindrome (24003030042).

The spelling of 12001020021 in words is "twelve billion, one million, twenty thousand, twenty-one".