221440431 has 24 divisors (see below), whose sum is σ = 305061120. Its totient is φ = 142857120.

The previous prime is 221440423. The next prime is 221440447. The reversal of 221440431 is 134044122.

It is not a de Polignac number, because 221440431 - 2³ = 221440423 is a prime.

It is a super-2 number, since 2×221440431² = 98071728962931522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221440398 and 221440407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221441431) 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 23 ways as a sum of consecutive naturals, for example, 926410 + ... + 926648.

It is an arithmetic number, because the mean of its divisors is an integer number (12710880).

Almost surely, 2^221440431 is an apocalyptic number.

221440431 is a deficient number, since it is larger than the sum of its proper divisors (83620689).

221440431 is an equidigital number, since it uses as much as digits as its factorization.

221440431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 447 (or 386 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 21.

The square root of 221440431 is about 14880.8746718733. The cubic root of 221440431 is about 604.9957252162.

Adding to 221440431 its reverse (134044122), we get a palindrome (355484553).

The spelling of 221440431 in words is "two hundred twenty-one million, four hundred forty thousand, four hundred thirty-one".