211210210220021 has 4 divisors (see below), whose sum is σ = 211309045135692. Its totient is φ = 211111375304352.

The previous prime is 211210210220011. The next prime is 211210210220027. The reversal of 211210210220021 is 120022012012112.

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 19952650651921 + 191257559568100 = 4466839^2 + 13829590^2 .

It is a cyclic number.

It is not a de Polignac number, because 211210210220021 - 2³⁴ = 211193030350837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211210210220027) 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, 49417454630 + ... + 49417458903.

It is an arithmetic number, because the mean of its divisors is an integer number (52827261283923).

Almost surely, 2^{211210210220021} is an apocalyptic number.

It is an amenable number.

211210210220021 is a deficient number, since it is larger than the sum of its proper divisors (98834915671).

211210210220021 is an equidigital number, since it uses as much as digits as its factorization.

211210210220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98834915670.

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

Adding to 211210210220021 its reverse (120022012012112), we get a palindrome (331232222232133).

The spelling of 211210210220021 in words is "two hundred eleven trillion, two hundred ten billion, two hundred ten million, two hundred twenty thousand, twenty-one".