638901823 has 8 divisors (see below), whose sum is σ = 730329248. Its totient is φ = 547513344.

The previous prime is 638901817. The next prime is 638901839. The reversal of 638901823 is 328109836.

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

It is not a de Polignac number, because 638901823 - 2¹³ = 638893631 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 (638901223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49315 + ... + 60907.

It is an arithmetic number, because the mean of its divisors is an integer number (91291156).

Almost surely, 2^638901823 is an apocalyptic number.

638901823 is a deficient number, since it is larger than the sum of its proper divisors (91427425).

638901823 is a wasteful number, since it uses less digits than its factorization.

638901823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19473.

The product of its (nonzero) digits is 62208, while the sum is 40.

The square root of 638901823 is about 25276.5073338861. The cubic root of 638901823 is about 861.2806874373.

The spelling of 638901823 in words is "six hundred thirty-eight million, nine hundred one thousand, eight hundred twenty-three".