646738 has 4 divisors (see below), whose sum is σ = 970110. Its totient is φ = 323368.

The previous prime is 646721. The next prime is 646757. The reversal of 646738 is 837646.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 413449 + 233289 = 643^2 + 483^2 .

It is a super-3 number, since 3×646738³ = 811533388638057816, which contains 333 as substring.

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 as a sum of consecutive naturals, namely, 161683 + ... + 161686.

2⁶⁴⁶⁷³⁸ is an apocalyptic number.

646738 is a deficient number, since it is larger than the sum of its proper divisors (323372).

646738 is a wasteful number, since it uses less digits than its factorization.

646738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323371.

The product of its digits is 24192, while the sum is 34.

The square root of 646738 is about 804.2002238249. The cubic root of 646738 is about 86.4787611994.

The spelling of 646738 in words is "six hundred forty-six thousand, seven hundred thirty-eight".