640442333 has 2 divisors, whose sum is σ = 640442334. Its totient is φ = 640442332.

The previous prime is 640442323. The next prime is 640442353. The reversal of 640442333 is 333244046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 636956644 + 3485689 = 25238^2 + 1867^2 .

It is a cyclic number.

It is not a de Polignac number, because 640442333 - 2⁶ = 640442269 is a prime.

It is equal to p_33322367 and since 640442333 and 33322367 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 640442296 and 640442305.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640442323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320221166 + 320221167.

It is an arithmetic number, because the mean of its divisors is an integer number (320221167).

Almost surely, 2^640442333 is an apocalyptic number.

It is an amenable number.

640442333 is a deficient number, since it is larger than the sum of its proper divisors (1).

640442333 is an equidigital number, since it uses as much as digits as its factorization.

640442333 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 29.

The square root of 640442333 is about 25306.9621448328. The cubic root of 640442333 is about 861.9723672826.

Adding to 640442333 its reverse (333244046), we get a palindrome (973686379).

The spelling of 640442333 in words is "six hundred forty million, four hundred forty-two thousand, three hundred thirty-three".