639329777 has 4 divisors (see below), whose sum is σ = 641227236. Its totient is φ = 637432320.

The previous prime is 639329773. The next prime is 639329783. The reversal of 639329777 is 777923936.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 337126321 + 302203456 = 18361^2 + 17384^2 .

It is a cyclic number.

It is not a de Polignac number, because 639329777 - 2² = 639329773 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639329773) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 948224 + ... + 948897.

It is an arithmetic number, because the mean of its divisors is an integer number (160306809).

Almost surely, 2^639329777 is an apocalyptic number.

It is an amenable number.

639329777 is a deficient number, since it is larger than the sum of its proper divisors (1897459).

639329777 is a wasteful number, since it uses less digits than its factorization.

639329777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1897458.

The product of its digits is 3000564, while the sum is 53.

The square root of 639329777 is about 25284.9713664066. The cubic root of 639329777 is about 861.4729476750.

The spelling of 639329777 in words is "six hundred thirty-nine million, three hundred twenty-nine thousand, seven hundred seventy-seven".