640145533 has 2 divisors, whose sum is σ = 640145534. Its totient is φ = 640145532.

The previous prime is 640145531. The next prime is 640145579. The reversal of 640145533 is 335541046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 547466404 + 92679129 = 23398^2 + 9627^2 .

It is a cyclic number.

It is not a de Polignac number, because 640145533 - 2¹ = 640145531 is a prime.

Together with 640145531, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 640145495 and 640145504.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640145531) 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 as a sum of consecutive naturals, namely, 320072766 + 320072767.

It is an arithmetic number, because the mean of its divisors is an integer number (320072767).

Almost surely, 2^640145533 is an apocalyptic number.

It is an amenable number.

640145533 is a deficient number, since it is larger than the sum of its proper divisors (1).

640145533 is an equidigital number, since it uses as much as digits as its factorization.

640145533 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21600, while the sum is 31.

The square root of 640145533 is about 25301.0974663156. The cubic root of 640145533 is about 861.8391921754.

Adding to 640145533 its reverse (335541046), we get a palindrome (975686579).

The spelling of 640145533 in words is "six hundred forty million, one hundred forty-five thousand, five hundred thirty-three".