640509069 has 8 divisors (see below), whose sum is σ = 854203840. Its totient is φ = 426910176.

The previous prime is 640509029. The next prime is 640509071. The reversal of 640509069 is 960905046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 640509069 - 2⁷ = 640508941 is a prime.

It is a super-2 number, since 2×640509069² = 820503734942493522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640509029) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6577 + ... + 36390.

It is an arithmetic number, because the mean of its divisors is an integer number (106775480).

Almost surely, 2^640509069 is an apocalyptic number.

It is an amenable number.

640509069 is a deficient number, since it is larger than the sum of its proper divisors (213694771).

640509069 is a wasteful number, since it uses less digits than its factorization.

640509069 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47939.

The product of its (nonzero) digits is 58320, while the sum is 39.

The square root of 640509069 is about 25308.2806409286. The cubic root of 640509069 is about 862.0023062727.

The spelling of 640509069 in words is "six hundred forty million, five hundred nine thousand, sixty-nine".