642784 has 24 divisors (see below), whose sum is σ = 1292760. Its totient is φ = 314496.

The previous prime is 642779. The next prime is 642791. The reversal of 642784 is 487246.

642784 = 67² + 68² + ... + 130².

642784 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1507 + ... + 1885.

It is an arithmetic number, because the mean of its divisors is an integer number (53865).

2⁶⁴²⁷⁸⁴ 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 642784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (646380).

642784 is an abundant number, since it is smaller than the sum of its proper divisors (649976).

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

642784 is a wasteful number, since it uses less digits than its factorization.

642784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 442 (or 434 counting only the distinct ones).

The product of its digits is 10752, while the sum is 31.

The square root of 642784 is about 801.7381118545. The cubic root of 642784 is about 86.3021640619.

The spelling of 642784 in words is "six hundred forty-two thousand, seven hundred eighty-four".