642888050809 has 27 divisors (see below), whose sum is σ = 683045000197. Its totient is φ = 605040543800.

The previous prime is 642888050767. The next prime is 642888050821. The reversal of 642888050809 is 908050888246.

The square root of 642888050809 is 801803.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 642888050809 - 2²¹ = 642885953657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642888050009) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1309344054 + ... + 1309344544.

Almost surely, 2^642888050809 is an apocalyptic number.

642888050809 is the 801803-rd square number.

642888050809 is the 400902-nd centered octagonal number.

It is an amenable number.

642888050809 is a deficient number, since it is larger than the sum of its proper divisors (40156949388).

642888050809 is an frugal number, since it uses more digits than its factorization.

642888050809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1170 (or 585 counting only the distinct ones).

The product of its (nonzero) digits is 8847360, while the sum is 58.

The spelling of 642888050809 in words is "six hundred forty-two billion, eight hundred eighty-eight million, fifty thousand, eight hundred nine".