642775571 has 4 divisors (see below), whose sum is σ = 643612200. Its totient is φ = 641938944.

The previous prime is 642775541. The next prime is 642775577. The reversal of 642775571 is 175577246.

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

It is a cyclic number.

It is not a de Polignac number, because 642775571 - 2¹⁰ = 642774547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642775577) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 417161 + ... + 418698.

It is an arithmetic number, because the mean of its divisors is an integer number (160903050).

Almost surely, 2^642775571 is an apocalyptic number.

642775571 is a deficient number, since it is larger than the sum of its proper divisors (836629).

642775571 is an equidigital number, since it uses as much as digits as its factorization.

642775571 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 836628.

The product of its digits is 411600, while the sum is 44.

The square root of 642775571 is about 25353.0189721067. The cubic root of 642775571 is about 863.0178682578.

It can be divided in two parts, 642775 and 571, that added together give a palindrome (643346).

The spelling of 642775571 in words is "six hundred forty-two million, seven hundred seventy-five thousand, five hundred seventy-one".