1210021000021 has 4 divisors (see below), whose sum is σ = 1210067924044. Its totient is φ = 1209974076000.

The previous prime is 1210021000007. The next prime is 1210021000043. The reversal of 1210021000021 is 1200001200121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 526910484996 + 683110515025 = 725886^2 + 826505^2 .

It is a cyclic number.

It is not a de Polignac number, because 1210021000021 - 2⁵ = 1210020999989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1210020999971 and 1210021000007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1210021000061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23423310 + ... + 23474911.

It is an arithmetic number, because the mean of its divisors is an integer number (302516981011).

Almost surely, 2^{1210021000021} is an apocalyptic number.

It is an amenable number.

1210021000021 is a deficient number, since it is larger than the sum of its proper divisors (46924023).

1210021000021 is an equidigital number, since it uses as much as digits as its factorization.

1210021000021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46924022.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 1210021000021 its reverse (1200001200121), we get a palindrome (2410022200142).

The spelling of 1210021000021 in words is "one trillion, two hundred ten billion, twenty-one million, twenty-one", and thus it is an aban number.