638021693 has 8 divisors (see below), whose sum is σ = 652471200. Its totient is φ = 623693488.

The previous prime is 638021677. The next prime is 638021723. The reversal of 638021693 is 396120836.

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 638021693 - 2⁴ = 638021677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638021093) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19646 + ... + 40767.

It is an arithmetic number, because the mean of its divisors is an integer number (81558900).

Almost surely, 2^638021693 is an apocalyptic number.

It is an amenable number.

638021693 is a deficient number, since it is larger than the sum of its proper divisors (14449507).

638021693 is a wasteful number, since it uses less digits than its factorization.

638021693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60651.

The product of its (nonzero) digits is 46656, while the sum is 38.

The square root of 638021693 is about 25259.0912940272. The cubic root of 638021693 is about 860.8850151061.

The spelling of 638021693 in words is "six hundred thirty-eight million, twenty-one thousand, six hundred ninety-three".