646942 has 4 divisors (see below), whose sum is σ = 970416. Its totient is φ = 323470.

The previous prime is 646937. The next prime is 646957. The reversal of 646942 is 249646.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 249646 = 2 ⋅124823.

It is a congruent number.

It is an unprimeable number.

646942 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161734 + ... + 161737.

It is an arithmetic number, because the mean of its divisors is an integer number (242604).

2⁶⁴⁶⁹⁴² is an apocalyptic number.

646942 is a deficient number, since it is larger than the sum of its proper divisors (323474).

646942 is a wasteful number, since it uses less digits than its factorization.

646942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323473.

The product of its digits is 10368, while the sum is 31.

The square root of 646942 is about 804.3270479102. The cubic root of 646942 is about 86.4878528835.

The spelling of 646942 in words is "six hundred forty-six thousand, nine hundred forty-two".