211320021 has 32 divisors (see below), whose sum is σ = 321979392. Its totient is φ = 122031360.

The previous prime is 211319993. The next prime is 211320041. The reversal of 211320021 is 120023112.

It is not a de Polignac number, because 211320021 - 2⁹ = 211319509 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 211319979 and 211320006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211320041) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 328326 + ... + 328968.

It is an arithmetic number, because the mean of its divisors is an integer number (10061856).

Almost surely, 2^211320021 is an apocalyptic number.

It is an amenable number.

211320021 is a deficient number, since it is larger than the sum of its proper divisors (110659371).

211320021 is a wasteful number, since it uses less digits than its factorization.

211320021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1113.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 211320021 is about 14536.8504498051. The cubic root of 211320021 is about 595.6350078568.

Adding to 211320021 its reverse (120023112), we get a palindrome (331343133).

The spelling of 211320021 in words is "two hundred eleven million, three hundred twenty thousand, twenty-one".