640892 has 24 divisors (see below), whose sum is σ = 1311744. Its totient is φ = 268272.

The previous prime is 640891. The next prime is 640901. The reversal of 640892 is 298046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640891) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1073 + ... + 1559.

It is an arithmetic number, because the mean of its divisors is an integer number (54656).

2⁶⁴⁰⁸⁹² is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640892, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (655872).

640892 is an abundant number, since it is smaller than the sum of its proper divisors (670852).

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

640892 is a wasteful number, since it uses less digits than its factorization.

640892 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 545 (or 543 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 640892 is about 800.5573058813. The cubic root of 640892 is about 86.2174055933.

The spelling of 640892 in words is "six hundred forty thousand, eight hundred ninety-two".