642368785 has 4 divisors (see below), whose sum is σ = 770842548. Its totient is φ = 513895024.

The previous prime is 642368773. The next prime is 642368791. The reversal of 642368785 is 587863246.

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

It can be written as a sum of positive squares in 2 ways, for example, as 80299521 + 562069264 = 8961^2 + 23708^2 .

It is a cyclic number.

It is not a de Polignac number, because 642368785 - 2¹¹ = 642366737 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64236874 + ... + 64236883.

It is an arithmetic number, because the mean of its divisors is an integer number (192710637).

Almost surely, 2^642368785 is an apocalyptic number.

It is an amenable number.

642368785 is a deficient number, since it is larger than the sum of its proper divisors (128473763).

642368785 is a wasteful number, since it uses less digits than its factorization.

642368785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128473762.

The product of its digits is 1935360, while the sum is 49.

The square root of 642368785 is about 25344.9952653379. The cubic root of 642368785 is about 862.8357737672.

The spelling of 642368785 in words is "six hundred forty-two million, three hundred sixty-eight thousand, seven hundred eighty-five".