6440431 has 2 divisors, whose sum is σ = 6440432. Its totient is φ = 6440430.

The previous prime is 6440429. The next prime is 6440443. The reversal of 6440431 is 1340446.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6440431 - 2¹ = 6440429 is a prime.

It is a super-2 number, since 2×6440431² = 82958302931522, which contains 22 as substring.

Together with 6440429, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6440471) 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 as a sum of consecutive naturals, namely, 3220215 + 3220216.

It is an arithmetic number, because the mean of its divisors is an integer number (3220216).

Almost surely, 2^6440431 is an apocalyptic number.

6440431 is a deficient number, since it is larger than the sum of its proper divisors (1).

6440431 is an equidigital number, since it uses as much as digits as its factorization.

6440431 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 6440431 is about 2537.8004255654. The cubic root of 6440431 is about 186.0536997607.

Adding to 6440431 its reverse (1340446), we get a palindrome (7780877).

The spelling of 6440431 in words is "six million, four hundred forty thousand, four hundred thirty-one".