638066785 has 8 divisors (see below), whose sum is σ = 765855720. Its totient is φ = 510336384.

The previous prime is 638066773. The next prime is 638066791. The reversal of 638066785 is 587660836.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 318515409 + 319551376 = 17847^2 + 17876^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 638066785 - 2¹³ = 638058593 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14701 + ... + 38629.

It is an arithmetic number, because the mean of its divisors is an integer number (95731965).

Almost surely, 2^638066785 is an apocalyptic number.

It is an amenable number.

638066785 is a deficient number, since it is larger than the sum of its proper divisors (127788935).

638066785 is a wasteful number, since it uses less digits than its factorization.

638066785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29267.

The product of its (nonzero) digits is 1451520, while the sum is 49.

The square root of 638066785 is about 25259.9838677700. The cubic root of 638066785 is about 860.9052955621.

The spelling of 638066785 in words is "six hundred thirty-eight million, sixty-six thousand, seven hundred eighty-five".