665942 has 16 divisors (see below), whose sum is σ = 1078272. Its totient is φ = 307560.

The previous prime is 665923. The next prime is 665947. The reversal of 665942 is 249566.

665942 = T₁₀₃ + T₁₀₄ + ... + T₁₇₁.

It is a plaindrome in base 9.

It is a junction number, because it is equal to n+sod(n) for n = 665899 and 665908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665947) 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, 1193 + ... + 1659.

It is an arithmetic number, because the mean of its divisors is an integer number (67392).

2⁶⁶⁵⁹⁴² is an apocalyptic number.

665942 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

665942 is a deficient number, since it is larger than the sum of its proper divisors (412330).

665942 is a wasteful number, since it uses less digits than its factorization.

665942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 523.

The product of its digits is 12960, while the sum is 32.

The square root of 665942 is about 816.0526943770. The cubic root of 665942 is about 87.3263822657.

The spelling of 665942 in words is "six hundred sixty-five thousand, nine hundred forty-two".