221640231 has 8 divisors (see below), whose sum is σ = 295624944. Its totient is φ = 147707840.

The previous prime is 221640131. The next prime is 221640277. The reversal of 221640231 is 132046122.

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

It is a cyclic number.

It is not a de Polignac number, because 221640231 - 2¹⁰ = 221639207 is a prime.

It is a super-2 number, since 2×221640231² = 98248783995466722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221640198 and 221640207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221640131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1806 + ... + 21131.

It is an arithmetic number, because the mean of its divisors is an integer number (36953118).

Almost surely, 2^221640231 is an apocalyptic number.

221640231 is a deficient number, since it is larger than the sum of its proper divisors (73984713).

221640231 is a wasteful number, since it uses less digits than its factorization.

221640231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26161.

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 221640231 is about 14887.5864733005. The cubic root of 221640231 is about 605.1776278744.

Adding to 221640231 its reverse (132046122), we get a palindrome (353686353).

The spelling of 221640231 in words is "two hundred twenty-one million, six hundred forty thousand, two hundred thirty-one".