221321431 has 4 divisors (see below), whose sum is σ = 228460864. Its totient is φ = 214182000.

The previous prime is 221321381. The next prime is 221321459. The reversal of 221321431 is 134123122.

It is a happy number.

221321431 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 221321431 - 2¹¹ = 221319383 is a prime.

It is a super-2 number, since 2×221321431² = 97966351639775522, 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 = 221321399 and 221321408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221321131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3569670 + ... + 3569731.

It is an arithmetic number, because the mean of its divisors is an integer number (57115216).

Almost surely, 2^221321431 is an apocalyptic number.

221321431 is a deficient number, since it is larger than the sum of its proper divisors (7139433).

221321431 is an equidigital number, since it uses as much as digits as its factorization.

221321431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7139432.

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

The square root of 221321431 is about 14876.8757136705. The cubic root of 221321431 is about 604.8873327979.

Adding to 221321431 its reverse (134123122), we get a palindrome (355444553).

The spelling of 221321431 in words is "two hundred twenty-one million, three hundred twenty-one thousand, four hundred thirty-one".