211021021220021 has 4 divisors (see below), whose sum is σ = 211145370674412. Its totient is φ = 210896671765632.

The previous prime is 211021021220003. The next prime is 211021021220089. The reversal of 211021021220021 is 120022120120112.

211021021220021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 182942531640625 + 28078489579396 = 13525625^2 + 5298914^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-211021021220021 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 (211021021220921) 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, 62174724650 + ... + 62174728043.

It is an arithmetic number, because the mean of its divisors is an integer number (52786342668603).

Almost surely, 2^{211021021220021} is an apocalyptic number.

It is an amenable number.

211021021220021 is a deficient number, since it is larger than the sum of its proper divisors (124349454391).

211021021220021 is a wasteful number, since it uses less digits than its factorization.

211021021220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124349454390.

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

Adding to 211021021220021 its reverse (120022120120112), we get a palindrome (331043141340133).

The spelling of 211021021220021 in words is "two hundred eleven trillion, twenty-one billion, twenty-one million, two hundred twenty thousand, twenty-one".