211021220021 has 8 divisors (see below), whose sum is σ = 212390575320. Its totient is φ = 209654710272.

The previous prime is 211021219991. The next prime is 211021220023. The reversal of 211021220021 is 120022120112.

It can be written as a sum of positive squares in 4 ways, for example, as 18838935025 + 192182284996 = 137255^2 + 438386^2 .

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 211021220021 - 2¹⁸ = 211020957877 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 211021219978 and 211021220005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211021220023) 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, 562490 + ... + 859323.

It is an arithmetic number, because the mean of its divisors is an integer number (26548821915).

Almost surely, 2^211021220021 is an apocalyptic number.

It is an amenable number.

211021220021 is a deficient number, since it is larger than the sum of its proper divisors (1369355299).

211021220021 is a wasteful number, since it uses less digits than its factorization.

211021220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1422775.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 211021220021 its reverse (120022120112), we get a palindrome (331043340133).

Subtracting from 211021220021 its reverse (120022120112), we obtain a palindrome (90999099909).

The spelling of 211021220021 in words is "two hundred eleven billion, twenty-one million, two hundred twenty thousand, twenty-one".