642291218 has 8 divisors (see below), whose sum is σ = 969006348. Its totient is φ = 319289104.

The previous prime is 642291203. The next prime is 642291227. The reversal of 642291218 is 812192246.

It can be written as a sum of positive squares in 2 ways, for example, as 470759809 + 171531409 = 21697^2 + 13097^2 .

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

It is a Curzon number.

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, 927821 + ... + 928512.

Almost surely, 2^642291218 is an apocalyptic number.

642291218 is a deficient number, since it is larger than the sum of its proper divisors (326715130).

642291218 is a wasteful number, since it uses less digits than its factorization.

642291218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1856508.

The product of its digits is 13824, while the sum is 35.

The square root of 642291218 is about 25343.4649959314. The cubic root of 642291218 is about 862.8010427954.

The spelling of 642291218 in words is "six hundred forty-two million, two hundred ninety-one thousand, two hundred eighteen".