21001211213021 has 8 divisors (see below), whose sum is σ = 22849850742264. Its totient is φ = 19185880504320.

The previous prime is 21001211212997. The next prime is 21001211213033. The reversal of 21001211213021 is 12031211210012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 27201904900 + 20974009308121 = 164930^2 + 4579739^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21001211213021 - 2³⁴ = 20984031343837 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001211213071) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8327203820 + ... + 8327206341.

It is an arithmetic number, because the mean of its divisors is an integer number (2856231342783).

Almost surely, 2^{21001211213021} is an apocalyptic number.

It is an amenable number.

21001211213021 is a deficient number, since it is larger than the sum of its proper divisors (1848639529243).

21001211213021 is a wasteful number, since it uses less digits than its factorization.

21001211213021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16654410271.

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 21001211213021 its reverse (12031211210012), we get a palindrome (33032422423033).

The spelling of 21001211213021 in words is "twenty-one trillion, one billion, two hundred eleven million, two hundred thirteen thousand, twenty-one".