640800290 has 16 divisors (see below), whose sum is σ = 1242166968. Its totient is φ = 236603136.

The previous prime is 640800253. The next prime is 640800301. The reversal of 640800290 is 92008046.

It can be written as a sum of positive squares in 4 ways, for example, as 276257641 + 364542649 = 16621^2 + 19093^2 .

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2464487 + ... + 2464746.

Almost surely, 2^640800290 is an apocalyptic number.

640800290 is a deficient number, since it is larger than the sum of its proper divisors (601366678).

640800290 is a wasteful number, since it uses less digits than its factorization.

640800290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4929253.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 640800290 is about 25314.0334597235. The cubic root of 640800290 is about 862.1329290068.

The spelling of 640800290 in words is "six hundred forty million, eight hundred thousand, two hundred ninety".