640201985 has 8 divisors (see below), whose sum is σ = 768398400. Its totient is φ = 512057584.

The previous prime is 640201973. The next prime is 640202011. The reversal of 640201985 is 589102046.

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

It is a cyclic number.

It is not a de Polignac number, because 640201985 - 2¹⁶ = 640136449 is a prime.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 23294 + ... + 42696.

It is an arithmetic number, because the mean of its divisors is an integer number (96049800).

Almost surely, 2^640201985 is an apocalyptic number.

It is an amenable number.

640201985 is a deficient number, since it is larger than the sum of its proper divisors (128196415).

640201985 is a wasteful number, since it uses less digits than its factorization.

640201985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26007.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 640201985 is about 25302.2130455026. The cubic root of 640201985 is about 861.8645255376.

The spelling of 640201985 in words is "six hundred forty million, two hundred one thousand, nine hundred eighty-five".