211223431 has 4 divisors (see below), whose sum is σ = 216375264. Its totient is φ = 206071600.

The previous prime is 211223413. The next prime is 211223471. The reversal of 211223431 is 134322112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 211223431 - 2⁹ = 211222919 is a prime.

It is a super-2 number, since 2×211223431² = 89230675606823522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 211223399 and 211223408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211223471) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2575855 + ... + 2575936.

It is an arithmetic number, because the mean of its divisors is an integer number (54093816).

Almost surely, 2^211223431 is an apocalyptic number.

211223431 is a deficient number, since it is larger than the sum of its proper divisors (5151833).

211223431 is an equidigital number, since it uses as much as digits as its factorization.

211223431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5151832.

The product of its digits is 288, while the sum is 19.

The square root of 211223431 is about 14533.5278236222. The cubic root of 211223431 is about 595.5442432225.

Adding to 211223431 its reverse (134322112), we get a palindrome (345545543).

The spelling of 211223431 in words is "two hundred eleven million, two hundred twenty-three thousand, four hundred thirty-one".