646442 has 8 divisors (see below), whose sum is σ = 1026756. Its totient is φ = 304192.

The previous prime is 646433. The next prime is 646453. The reversal of 646442 is 244646.

It can be written as a sum of positive squares in 2 ways, for example, as 609961 + 36481 = 781^2 + 191^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9473 + ... + 9540.

2⁶⁴⁶⁴⁴² is an apocalyptic number.

646442 is a deficient number, since it is larger than the sum of its proper divisors (380314).

646442 is a wasteful number, since it uses less digits than its factorization.

646442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19032.

The product of its digits is 4608, while the sum is 26.

The square root of 646442 is about 804.0161689916. The cubic root of 646442 is about 86.4655659439.

Subtracting from 646442 its sum of digits (26), we obtain a square (646416 = 804²).

It can be divided in two parts, 64644 and 2, that added together give a palindrome (64646).

The spelling of 646442 in words is "six hundred forty-six thousand, four hundred forty-two".