638404669 has 8 divisors (see below), whose sum is σ = 753141248. Its totient is φ = 529552080.

The previous prime is 638404651. The next prime is 638404673. The reversal of 638404669 is 966404836.

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 638404669 - 2⁹ = 638404157 is a prime.

It is a super-2 number, since 2×638404669² = 815121042801999122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638404639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1470762 + ... + 1471195.

It is an arithmetic number, because the mean of its divisors is an integer number (94142656).

Almost surely, 2^638404669 is an apocalyptic number.

It is an amenable number.

638404669 is a deficient number, since it is larger than the sum of its proper divisors (114736579).

638404669 is a wasteful number, since it uses less digits than its factorization.

638404669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2941995.

The product of its (nonzero) digits is 746496, while the sum is 46.

The square root of 638404669 is about 25266.6711103778. The cubic root of 638404669 is about 861.0572309609.

The spelling of 638404669 in words is "six hundred thirty-eight million, four hundred four thousand, six hundred sixty-nine".