221305431 has 8 divisors (see below), whose sum is σ = 295469824. Its totient is φ = 147339000.

The previous prime is 221305421. The next prime is 221305453. The reversal of 221305431 is 134503122.

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

It is not a de Polignac number, because 221305431 - 2²⁷ = 87087703 is a prime.

It is a super-2 number, since 2×221305431² = 97952187580191522, 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 = 221305398 and 221305407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221305421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46861 + ... + 51366.

It is an arithmetic number, because the mean of its divisors is an integer number (36933728).

Almost surely, 2^221305431 is an apocalyptic number.

221305431 is a deficient number, since it is larger than the sum of its proper divisors (74164393).

221305431 is an equidigital number, since it uses as much as digits as its factorization.

221305431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98981.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 221305431 is about 14876.3379566344. The cubic root of 221305431 is about 604.8727560643.

Adding to 221305431 its reverse (134503122), we get a palindrome (355808553).

The spelling of 221305431 in words is "two hundred twenty-one million, three hundred five thousand, four hundred thirty-one".