639216730 has 8 divisors (see below), whose sum is σ = 1150590132. Its totient is φ = 255686688.

The previous prime is 639216709. The next prime is 639216731. The reversal of 639216730 is 37612936.

It can be written as a sum of positive squares in 2 ways, for example, as 591316489 + 47900241 = 24317^2 + 6921^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 639216730.

It is not an unprimeable number, because it can be changed into a prime (639216731) 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, 31960827 + ... + 31960846.

Almost surely, 2^639216730 is an apocalyptic number.

639216730 is a deficient number, since it is larger than the sum of its proper divisors (511373402).

639216730 is a wasteful number, since it uses less digits than its factorization.

639216730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63921680.

The product of its (nonzero) digits is 40824, while the sum is 37.

The square root of 639216730 is about 25282.7358092434. The cubic root of 639216730 is about 861.4221691480.

The spelling of 639216730 in words is "six hundred thirty-nine million, two hundred sixteen thousand, seven hundred thirty".