639340469 has 4 divisors (see below), whose sum is σ = 654208896. Its totient is φ = 624472044.

The previous prime is 639340447. The next prime is 639340487. The reversal of 639340469 is 964043936.

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 639340469 - 2²⁰ = 638291893 is a prime.

It is a super-4 number, since 4×639340469⁴ (a number of 36 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639340439) 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, 7434149 + ... + 7434234.

It is an arithmetic number, because the mean of its divisors is an integer number (163552224).

Almost surely, 2^639340469 is an apocalyptic number.

It is an amenable number.

639340469 is a deficient number, since it is larger than the sum of its proper divisors (14868427).

639340469 is a wasteful number, since it uses less digits than its factorization.

639340469 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14868426.

The product of its (nonzero) digits is 419904, while the sum is 44.

The square root of 639340469 is about 25285.1827954634. The cubic root of 639340469 is about 861.4777500048.

The spelling of 639340469 in words is "six hundred thirty-nine million, three hundred forty thousand, four hundred sixty-nine".