640042135 has 4 divisors (see below), whose sum is σ = 768050568. Its totient is φ = 512033704.

The previous prime is 640042127. The next prime is 640042147. The reversal of 640042135 is 531240046.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 640042135 - 2³ = 640042127 is a prime.

It is a Duffinian number.

It is a congruent 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 3 ways as a sum of consecutive naturals, for example, 64004209 + ... + 64004218.

It is an arithmetic number, because the mean of its divisors is an integer number (192012642).

Almost surely, 2^640042135 is an apocalyptic number.

640042135 is a deficient number, since it is larger than the sum of its proper divisors (128008433).

640042135 is a wasteful number, since it uses less digits than its factorization.

640042135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128008432.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 640042135 is about 25299.0540336986. The cubic root of 640042135 is about 861.7927874948.

The spelling of 640042135 in words is "six hundred forty million, forty-two thousand, one hundred thirty-five".