640305283 has 4 divisors (see below), whose sum is σ = 640961640. Its totient is φ = 639648928.

The previous prime is 640305277. The next prime is 640305287. The reversal of 640305283 is 382503046.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 640305283 - 2⁵ = 640305251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640305287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 326713 + ... + 328666.

It is an arithmetic number, because the mean of its divisors is an integer number (160240410).

Almost surely, 2^640305283 is an apocalyptic number.

640305283 is a deficient number, since it is larger than the sum of its proper divisors (656357).

640305283 is an equidigital number, since it uses as much as digits as its factorization.

640305283 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 656356.

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 640305283 is about 25304.2542470629. The cubic root of 640305283 is about 861.9108776244.

The spelling of 640305283 in words is "six hundred forty million, three hundred five thousand, two hundred eighty-three".