640837169 has 4 divisors (see below), whose sum is σ = 732385344. Its totient is φ = 549288996.

The previous prime is 640837129. The next prime is 640837189. The reversal of 640837169 is 961738046.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 640837169 - 2²⁰ = 639788593 is a prime.

It is a super-2 number, since 2×640837169² = 821344554343869122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640837129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45774077 + ... + 45774090.

It is an arithmetic number, because the mean of its divisors is an integer number (183096336).

Almost surely, 2^640837169 is an apocalyptic number.

It is an amenable number.

640837169 is a deficient number, since it is larger than the sum of its proper divisors (91548175).

640837169 is an equidigital number, since it uses as much as digits as its factorization.

640837169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91548174.

The product of its (nonzero) digits is 217728, while the sum is 44.

The square root of 640837169 is about 25314.7618791882. The cubic root of 640837169 is about 862.1494676959.

The spelling of 640837169 in words is "six hundred forty million, eight hundred thirty-seven thousand, one hundred sixty-nine".