642578 has 4 divisors (see below), whose sum is σ = 963870. Its totient is φ = 321288.

The previous prime is 642563. The next prime is 642581. The reversal of 642578 is 875246.

Added to its reverse (875246) it gives a square (1517824 = 1232²).

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., 588289 + 54289 = 767^2 + 233^2 .

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642578.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160643 + ... + 160646.

2⁶⁴²⁵⁷⁸ is an apocalyptic number.

642578 is a deficient number, since it is larger than the sum of its proper divisors (321292).

642578 is a wasteful number, since it uses less digits than its factorization.

642578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321291.

The product of its digits is 13440, while the sum is 32.

The square root of 642578 is about 801.6096306807. The cubic root of 642578 is about 86.2929436783.

Adding to 642578 its reverse (875246), we get a square (1517824 = 1232²).

The spelling of 642578 in words is "six hundred forty-two thousand, five hundred seventy-eight".