639351577 has 6 divisors (see below), whose sum is σ = 674773098. Its totient is φ = 605701152.

The previous prime is 639351569. The next prime is 639351611. The reversal of 639351577 is 775153936.

It can be written as a sum of positive squares in only one way, i.e., 493328521 + 146023056 = 22211^2 + 12084^2 .

It is not a de Polignac number, because 639351577 - 2³ = 639351569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639351547) 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, 885168 + ... + 885889.

It is an arithmetic number, because the mean of its divisors is an integer number (112462183).

Almost surely, 2^639351577 is an apocalyptic number.

It is an amenable number.

639351577 is a deficient number, since it is larger than the sum of its proper divisors (35421521).

639351577 is a wasteful number, since it uses less digits than its factorization.

639351577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1771095 (or 1771076 counting only the distinct ones).

The product of its digits is 595350, while the sum is 46.

The square root of 639351577 is about 25285.4024488439. The cubic root of 639351577 is about 861.4827391251.

It can be divided in two parts, 6393 and 51577, that added together give a triangular number (57970 = T₃₄₀).

The spelling of 639351577 in words is "six hundred thirty-nine million, three hundred fifty-one thousand, five hundred seventy-seven".