665742 has 48 divisors (see below), whose sum is σ = 1685376. Its totient is φ = 171600.

The previous prime is 665723. The next prime is 665747. The reversal of 665742 is 247566.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665747) 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, 5017 + ... + 5147.

It is an arithmetic number, because the mean of its divisors is an integer number (35112).

2⁶⁶⁵⁷⁴² is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665742, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (842688).

665742 is an abundant number, since it is smaller than the sum of its proper divisors (1019634).

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

665742 is a wasteful number, since it uses less digits than its factorization.

665742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 154 counting only the distinct ones).

The product of its digits is 10080, while the sum is 30.

The square root of 665742 is about 815.9301440687. The cubic root of 665742 is about 87.3176392494.

The spelling of 665742 in words is "six hundred sixty-five thousand, seven hundred forty-two".