221031213 has 24 divisors (see below), whose sum is σ = 320106528. Its totient is φ = 135600192.

The previous prime is 221031211. The next prime is 221031247. The reversal of 221031213 is 312130122.

It is not a de Polignac number, because 221031213 - 2¹ = 221031211 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 221031192 and 221031201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221031211) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 276931 + ... + 277727.

It is an arithmetic number, because the mean of its divisors is an integer number (13337772).

Almost surely, 2^221031213 is an apocalyptic number.

It is an amenable number.

221031213 is a deficient number, since it is larger than the sum of its proper divisors (99075315).

221031213 is a wasteful number, since it uses less digits than its factorization.

221031213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1373 (or 1360 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 221031213 is about 14867.1185170496. The cubic root of 221031213 is about 604.6228216154.

Adding to 221031213 its reverse (312130122), we get a palindrome (533161335).

The spelling of 221031213 in words is "two hundred twenty-one million, thirty-one thousand, two hundred thirteen".