640121135 has 8 divisors (see below), whose sum is σ = 773301600. Its totient is φ = 508659424.

The previous prime is 640121123. The next prime is 640121203. The reversal of 640121135 is 531121046.

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 640121135 - 2⁶ = 640121071 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640121135.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 428867 + ... + 430356.

It is an arithmetic number, because the mean of its divisors is an integer number (96662700).

Almost surely, 2^640121135 is an apocalyptic number.

640121135 is a deficient number, since it is larger than the sum of its proper divisors (133180465).

640121135 is a wasteful number, since it uses less digits than its factorization.

640121135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 859377.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 640121135 is about 25300.6153087232. The cubic root of 640121135 is about 861.8282428841.

The spelling of 640121135 in words is "six hundred forty million, one hundred twenty-one thousand, one hundred thirty-five".