211212210021 has 4 divisors (see below), whose sum is σ = 281616280032. Its totient is φ = 140808140012.

The previous prime is 211212209963. The next prime is 211212210049. The reversal of 211212210021 is 120012212112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 211212210021 - 2¹³ = 211212201829 is a prime.

It is a super-2 number, since 2×211212210021² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211212210421) 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, 35202035001 + ... + 35202035006.

It is an arithmetic number, because the mean of its divisors is an integer number (70404070008).

Almost surely, 2^211212210021 is an apocalyptic number.

It is an amenable number.

211212210021 is a deficient number, since it is larger than the sum of its proper divisors (70404070011).

211212210021 is an equidigital number, since it uses as much as digits as its factorization.

211212210021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70404070010.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 211212210021 its reverse (120012212112), we get a palindrome (331224422133).

The spelling of 211212210021 in words is "two hundred eleven billion, two hundred twelve million, two hundred ten thousand, twenty-one".