211530021 has 8 divisors (see below), whose sum is σ = 296884320. Its totient is φ = 133597872.

The previous prime is 211530001. The next prime is 211530037. The reversal of 211530021 is 120035112.

211530021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 211530021 - 2¹⁴ = 211513637 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211530001) 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, 1855470 + ... + 1855583.

It is an arithmetic number, because the mean of its divisors is an integer number (37110540).

Almost surely, 2^211530021 is an apocalyptic number.

It is an amenable number.

211530021 is a deficient number, since it is larger than the sum of its proper divisors (85354299).

211530021 is a wasteful number, since it uses less digits than its factorization.

211530021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3711075.

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 211530021 is about 14544.0716788663. The cubic root of 211530021 is about 595.8322473168.

Adding to 211530021 its reverse (120035112), we get a palindrome (331565133).

The spelling of 211530021 in words is "two hundred eleven million, five hundred thirty thousand, twenty-one".