840221231 has 4 divisors (see below), whose sum is σ = 843345000. Its totient is φ = 837097464.

The previous prime is 840221227. The next prime is 840221233. The reversal of 840221231 is 132122048.

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 840221231 - 2² = 840221227 is a prime.

It is a super-2 number, since 2×840221231² = 1411943434046310722, 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 = 840221197 and 840221206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840221233) 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, 1561481 + ... + 1562018.

It is an arithmetic number, because the mean of its divisors is an integer number (210836250).

Almost surely, 2^840221231 is an apocalyptic number.

840221231 is a deficient number, since it is larger than the sum of its proper divisors (3123769).

840221231 is a wasteful number, since it uses less digits than its factorization.

840221231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3123768.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 840221231 is about 28986.5698384614. The cubic root of 840221231 is about 943.6216221382.

Adding to 840221231 its reverse (132122048), we get a palindrome (972343279).

The spelling of 840221231 in words is "eight hundred forty million, two hundred twenty-one thousand, two hundred thirty-one".