643534169 has 6 divisors (see below), whose sum is σ = 651006990. Its totient is φ = 636066816.

The previous prime is 643534159. The next prime is 643534193. The reversal of 643534169 is 961435346.

It can be written as a sum of positive squares in 3 ways, for example, as 83028544 + 560505625 = 9112^2 + 23675^2 .

It is not a de Polignac number, because 643534169 - 2¹² = 643530073 is a prime.

It is a super-2 number, since 2×643534169² = 828272453341041122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643534159) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 237977 + ... + 240665.

It is an arithmetic number, because the mean of its divisors is an integer number (108501165).

Almost surely, 2^643534169 is an apocalyptic number.

It is an amenable number.

643534169 is a deficient number, since it is larger than the sum of its proper divisors (7472821).

643534169 is an frugal number, since it uses more digits than its factorization.

643534169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5467 (or 2778 counting only the distinct ones).

The product of its digits is 233280, while the sum is 41.

The square root of 643534169 is about 25367.9752641002. The cubic root of 643534169 is about 863.3572434490.

It can be divided in two parts, 6435 and 34169, that added together give a palindrome (40604).

The spelling of 643534169 in words is "six hundred forty-three million, five hundred thirty-four thousand, one hundred sixty-nine".