640473313 has 2 divisors, whose sum is σ = 640473314. Its totient is φ = 640473312.

The previous prime is 640473307. The next prime is 640473349. The reversal of 640473313 is 313374046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 365842129 + 274631184 = 19127^2 + 16572^2 .

It is a cyclic number.

It is not a de Polignac number, because 640473313 - 2¹³ = 640465121 is a prime.

It is not a weakly prime, because it can be changed into another prime (640473373) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320236656 + 320236657.

It is an arithmetic number, because the mean of its divisors is an integer number (320236657).

Almost surely, 2^640473313 is an apocalyptic number.

It is an amenable number.

640473313 is a deficient number, since it is larger than the sum of its proper divisors (1).

640473313 is an equidigital number, since it uses as much as digits as its factorization.

640473313 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 31.

The square root of 640473313 is about 25307.5742219597. The cubic root of 640473313 is about 861.9862657358.

The spelling of 640473313 in words is "six hundred forty million, four hundred seventy-three thousand, three hundred thirteen".