210240221 has 6 divisors (see below), whose sum is σ = 213747066. Its totient is φ = 206790000.

The previous prime is 210240211. The next prime is 210240223. The reversal of 210240221 is 122042012.

It can be written as a sum of positive squares in 3 ways, for example, as 31483321 + 178756900 = 5611^2 + 13370^2 .

It is not a de Polignac number, because 210240221 - 2⁶ = 210240157 is a prime.

It is a super-2 number, since 2×210240221² = 88401901052257682, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 210240196 and 210240205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210240223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 24530 + ... + 31971.

It is an arithmetic number, because the mean of its divisors is an integer number (35624511).

Almost surely, 2^210240221 is an apocalyptic number.

It is an amenable number.

210240221 is a deficient number, since it is larger than the sum of its proper divisors (3506845).

210240221 is an frugal number, since it uses more digits than its factorization.

210240221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56623 (or 56562 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 210240221 is about 14499.6627891824. The cubic root of 210240221 is about 594.6187525423.

Adding to 210240221 its reverse (122042012), we get a palindrome (332282233).

The spelling of 210240221 in words is "two hundred ten million, two hundred forty thousand, two hundred twenty-one".