642640433 has 2 divisors, whose sum is σ = 642640434. Its totient is φ = 642640432.

The previous prime is 642640403. The next prime is 642640441. The reversal of 642640433 is 334046246.

642640433 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 444872464 + 197767969 = 21092^2 + 14063^2 .

It is a cyclic number.

It is not a de Polignac number, because 642640433 - 2¹⁰ = 642639409 is a prime.

It is a super-2 number, since 2×642640433² = 825973452252854978, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 642640433.

It is not a weakly prime, because it can be changed into another prime (642640403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321320216 + 321320217.

It is an arithmetic number, because the mean of its divisors is an integer number (321320217).

Almost surely, 2^642640433 is an apocalyptic number.

It is an amenable number.

642640433 is a deficient number, since it is larger than the sum of its proper divisors (1).

642640433 is an equidigital number, since it uses as much as digits as its factorization.

642640433 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 41472, while the sum is 32.

The square root of 642640433 is about 25350.3537056192. The cubic root of 642640433 is about 862.9573833399.

Adding to 642640433 its reverse (334046246), we get a palindrome (976686679).

The spelling of 642640433 in words is "six hundred forty-two million, six hundred forty thousand, four hundred thirty-three".