640134 has 48 divisors (see below), whose sum is σ = 1566864. Its totient is φ = 187200.

The previous prime is 640127. The next prime is 640139. The reversal of 640134 is 431046.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640139) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10464 + ... + 10524.

It is an arithmetic number, because the mean of its divisors is an integer number (32643).

2⁶⁴⁰¹³⁴ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640134, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (783432).

640134 is an abundant number, since it is smaller than the sum of its proper divisors (926730).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640134 is a wasteful number, since it uses less digits than its factorization.

640134 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 640134 is about 800.0837456167. The cubic root of 640134 is about 86.1834016451.

The spelling of 640134 in words is "six hundred forty thousand, one hundred thirty-four".