21210212201021 has 4 divisors (see below), whose sum is σ = 21210223013532. Its totient is φ = 21210201388512.

The previous prime is 21210212200987. The next prime is 21210212201041. The reversal of 21210212201021 is 12010221201212.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 8865804002500 + 12344408198521 = 2977550^2 + 3513461^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210212201021 - 2¹⁰ = 21210212199997 is a prime.

It is a super-2 number, since 2×21210212201021² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210212201041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1544120 + ... + 6693633.

It is an arithmetic number, because the mean of its divisors is an integer number (5302555753383).

Almost surely, 2^{21210212201021} is an apocalyptic number.

It is an amenable number.

21210212201021 is a deficient number, since it is larger than the sum of its proper divisors (10812511).

21210212201021 is an equidigital number, since it uses as much as digits as its factorization.

21210212201021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10812510.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21210212201021 its reverse (12010221201212), we get a palindrome (33220433402233).

The spelling of 21210212201021 in words is "twenty-one trillion, two hundred ten billion, two hundred twelve million, two hundred one thousand, twenty-one".