642544642 has 4 divisors (see below), whose sum is σ = 963816966. Its totient is φ = 321272320.

The previous prime is 642544621. The next prime is 642544687. The reversal of 642544642 is 246445246.

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., 620557921 + 21986721 = 24911^2 + 4689^2 .

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, 160636159 + ... + 160636162.

Almost surely, 2^642544642 is an apocalyptic number.

642544642 is a deficient number, since it is larger than the sum of its proper divisors (321272324).

642544642 is a wasteful number, since it uses less digits than its factorization.

642544642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321272323.

The product of its digits is 184320, while the sum is 37.

The square root of 642544642 is about 25348.4642927338. The cubic root of 642544642 is about 862.9145041734.

Adding to 642544642 its reverse (246445246), we get a palindrome (888989888).

The spelling of 642544642 in words is "six hundred forty-two million, five hundred forty-four thousand, six hundred forty-two".