639905095 has 4 divisors (see below), whose sum is σ = 767886120. Its totient is φ = 511924072.

The previous prime is 639905087. The next prime is 639905099. The reversal of 639905095 is 590509936.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 639905095 - 2³ = 639905087 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639905099) 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, 63990505 + ... + 63990514.

It is an arithmetic number, because the mean of its divisors is an integer number (191971530).

Almost surely, 2^639905095 is an apocalyptic number.

639905095 is a deficient number, since it is larger than the sum of its proper divisors (127981025).

639905095 is a wasteful number, since it uses less digits than its factorization.

639905095 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127981024.

The product of its (nonzero) digits is 328050, while the sum is 46.

The square root of 639905095 is about 25296.3454870461. The cubic root of 639905095 is about 861.7312766936.

The spelling of 639905095 in words is "six hundred thirty-nine million, nine hundred five thousand, ninety-five".