642015818 has 8 divisors (see below), whose sum is σ = 981194148. Its totient is φ = 314951104.

The previous prime is 642015811. The next prime is 642015821. The reversal of 642015818 is 818510246.

It can be written as a sum of positive squares in 2 ways, for example, as 565155529 + 76860289 = 23773^2 + 8767^2 .

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

It is not an unprimeable number, because it can be changed into a prime (642015811) by changing a digit.

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, 3028271 + ... + 3028482.

Almost surely, 2^642015818 is an apocalyptic number.

642015818 is a deficient number, since it is larger than the sum of its proper divisors (339178330).

642015818 is a wasteful number, since it uses less digits than its factorization.

642015818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6056808.

The product of its (nonzero) digits is 15360, while the sum is 35.

The square root of 642015818 is about 25338.0310600488. The cubic root of 642015818 is about 862.6777086182.

The spelling of 642015818 in words is "six hundred forty-two million, fifteen thousand, eight hundred eighteen".