640202505 has 8 divisors (see below), whose sum is σ = 1024324032. Its totient is φ = 341441328.

The previous prime is 640202471. The next prime is 640202509. The reversal of 640202505 is 505202046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 640202505 - 2⁶ = 640202441 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (640202509) by changing a digit.

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, 21340069 + ... + 21340098.

It is an arithmetic number, because the mean of its divisors is an integer number (128040504).

Almost surely, 2^640202505 is an apocalyptic number.

It is an amenable number.

640202505 is a deficient number, since it is larger than the sum of its proper divisors (384121527).

640202505 is a wasteful number, since it uses less digits than its factorization.

640202505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42680175.

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 640202505 is about 25302.2233212815. The cubic root of 640202505 is about 861.8647588856.

The spelling of 640202505 in words is "six hundred forty million, two hundred two thousand, five hundred five".